diff --git a/bld/CLMBuildNamelist.pm b/bld/CLMBuildNamelist.pm
index 46840cdaf7..9cfa537ff8 100755
--- a/bld/CLMBuildNamelist.pm
+++ b/bld/CLMBuildNamelist.pm
@@ -2039,6 +2039,7 @@ sub setup_logic_glacier {
      add_default($opts,  $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'glacier_region_behavior');
      add_default($opts,  $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'glacier_region_melt_behavior');
      add_default($opts,  $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'glacier_region_ice_runoff_behavior');
+     add_default($opts,  $nl_flags->{'inputdata_rootdir'}, $definition, $defaults, $nl, 'glacier_region_rain_to_snow_behavior');
   }
 }
 
diff --git a/bld/namelist_files/namelist_defaults_clm4_5.xml b/bld/namelist_files/namelist_defaults_clm4_5.xml
index 21809bcf9c..280217f661 100644
--- a/bld/namelist_files/namelist_defaults_clm4_5.xml
+++ b/bld/namelist_files/namelist_defaults_clm4_5.xml
@@ -336,6 +336,8 @@ attributes from the config_cache.xml file (with keys converted to upper-case).
      Antarctica: remains_ice -->
 <glacier_region_ice_runoff_behavior>'melted','melted','remains_ice','remains_ice'</glacier_region_ice_runoff_behavior>
 
+<glacier_region_rain_to_snow_behavior>'converted_to_snow','converted_to_snow','converted_to_snow','converted_to_snow'</glacier_region_rain_to_snow_behavior>
+
 <!-- This parameter is tied (in a scientific sense) to h2osno_max: For large
      values of h2osno_max, glc_snow_persistence_max_days should be 0; for small
      values of h2osno_max, glc_snow_persistence_max_days should be non-zero. For
diff --git a/bld/namelist_files/namelist_definition_clm4_5.xml b/bld/namelist_files/namelist_definition_clm4_5.xml
index 09af1a1756..3ea41dbacf 100644
--- a/bld/namelist_files/namelist_definition_clm4_5.xml
+++ b/bld/namelist_files/namelist_definition_clm4_5.xml
@@ -507,6 +507,23 @@ Allowed values are:
 Only applies when melt_non_icesheet_ice_runoff is .true.
 </entry>
 
+<entry id="glacier_region_rain_to_snow_behavior" type="char*32(10)" category="clm_physics"
+       group="clm_glacier_behavior"
+       valid_values="converted_to_snow,runs_off" >
+When rain-snow repartitioning / downscaling results in rain being converted to
+snow, the behavior of the resulting additional snow.
+First item corresponds to GLACIER_REGION with ID 0 in the surface dataset,
+second to GLACIER_REGION with ID 1, etc.
+Allowed values are:
+'converted_to_snow': rain is converted to snow, with a corresponding sensible
+   heat flux correction
+'runs_off': rather than being converted to snow, the excess rain runs off
+   immediately
+IMPORTANT NOTE: Unlike other glacier_region*behavior namelist options, this
+option applies to all landunit types in the given regions.
+Only applies when repartition_rain_snow is .true.
+</entry>
+
 <entry id="glc_snow_persistence_max_days" type="integer" category="clm_physics"
        group="clm_inparm" valid_values="" >
 Number of days before one considers the perennially snow-covered point 'land ice'
diff --git a/cime_config/testdefs/testlist_clm.xml b/cime_config/testdefs/testlist_clm.xml
index af084cfdf3..3055bfb17e 100644
--- a/cime_config/testdefs/testlist_clm.xml
+++ b/cime_config/testdefs/testlist_clm.xml
@@ -382,6 +382,15 @@
       <option name="wallclock">00:20:00</option>
     </options>
   </test>
+  <test name="ERP_D_P36x2_Ld3" grid="f10_f10_musgs" compset="I1850Clm50BgcCrop" testmods="clm/rain_to_snow_runs_off">
+    <machines>
+      <machine name="cheyenne" compiler="intel" category="aux_clm">
+        <options>
+          <option name="wallclock">00:20:00</option>
+        </options>
+      </machine>
+    </machines>
+  </test>
   <test name="ERP_D_P36x2_Ld3" grid="f10_f10_musgs" compset="I2000Clm50BgcCrop" testmods="clm/cropColdStart">
     <machines>
       <machine name="cheyenne" compiler="intel" category="aux_clm"/>
diff --git a/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/include_user_mods b/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/include_user_mods
new file mode 100644
index 0000000000..fe0e18cf88
--- /dev/null
+++ b/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/include_user_mods
@@ -0,0 +1 @@
+../default
diff --git a/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/user_nl_clm b/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/user_nl_clm
new file mode 100644
index 0000000000..ac152ceb5c
--- /dev/null
+++ b/cime_config/testdefs/testmods_dirs/clm/rain_to_snow_runs_off/user_nl_clm
@@ -0,0 +1,2 @@
+ glacier_region_rain_to_snow_behavior = 'converted_to_snow','converted_to_snow','runs_off','converted_to_snow'
+
diff --git a/doc/ChangeSum b/doc/ChangeSum
index 34b3b0b71f..88caaeffdb 100644
--- a/doc/ChangeSum
+++ b/doc/ChangeSum
@@ -1,5 +1,6 @@
 Tag                   Who      Date  Summary
 ============================================================================================================================
+release-clm5.0.15    sacks 12/06/2018 Option for rain-to-snow to immediately run off in some regions
 release-clm5.0.14     erik 11/29/2018 Update cime and fix surface dataset for f05 1850 non-crop case
 release-clm5.0.13     erik 11/14/2018 Update externals with new CO2/presearo/rtm/mosart, add science_support, change testing
 release-clm5.0.12     erik 11/03/2018 New IC files for clm45/clm50 coupled cases, add 2010 compset
diff --git a/doc/release-clm5.0.ChangeLog b/doc/release-clm5.0.ChangeLog
index fa91db9ae2..fafdfe6902 100644
--- a/doc/release-clm5.0.ChangeLog
+++ b/doc/release-clm5.0.ChangeLog
@@ -1,4 +1,178 @@
 ===============================================================
+Tag name:  release-clm5.0.15
+Originator(s):  sacks (Bill Sacks)
+Date: Thu Dec  6 10:14:30 MST 2018
+One-line Summary: Option for rain-to-snow to immediately run off in some regions
+
+Purpose of this version:
+------------------------
+
+Up until now: When repartition_rain_snow is .true. (which is the default
+for CLM5), rain that falls when the near-surface temperature is cold is
+converted to snow. This repartitioning was put in place for two
+reasons: (1) Downscaling to elevation classes: changing the balance
+between rain and snow for different elevation classes; (2) Correcting
+problems in CAM. However, members of the Land Ice Working Group would
+like to change this behavior so that, when CAM produces cold-temperature
+rain, this rain immediately runs off rather than being converted to
+snow. The purpose of this is to reduce the too-high SMB over portions of
+Greenland in CESM2 coupled runs (which results in part from CAM's
+generation of liquid precipitation despite very cold temperatures).
+
+This new behavior is implemented in a glacier region-specific manner,
+based on a new namelist flag, glacier_region_rain_to_snow_behavior. It
+is not at all ideal to make this aspect of the physics differ by region,
+but this has been requested by members of the Land Ice Working Group in
+order to address biases over Greenland while having minimal impact on
+the climate (so that the climate can stay very similar to that of the
+official CMIP6 runs). Note that, unlike other glacier region-specific
+behaviors, this one applies to all landunits, not just glaciers. This
+also seems a bit non-ideal, but we want the physics to be the same for
+all landunit types in a given region, and we also want this behavior to
+apply to vegetated columns because they are used for glacial
+inception (and we want this alternate behavior to apply to glacial
+inception, too, in order to decrease some instances of inception).
+
+The justification for this new physics is: In the case of (1) above: If
+CAM is generating rain at a given elevation / temperature, that doesn't
+necessarily imply that an equal water equivalent of snow would be
+generated at a higher elevation / lower temperature: indeed, in reality,
+there might not be any precipitation falling at that higher elevation /
+lower temperature. In the case of (2) above: There seem to be problems
+with CAM's microphysics that cause it to produce too much rain when
+temperatures are very cold; it seems (at least to some people) equally
+justifiable to throw this cold rain away (by sending it to the ocean as
+runoff) as it is to convert this cold rain to snow.
+
+Note: I don't think any changes are needed in
+BalanceCheck (unfortunately), since BalanceCheck currently uses the
+post-downscaling precipitation fluxes, and the pre-lnd2atm runoff
+fluxes (i.e., the new runoff flux isn't included in the terms in
+BalanceCheck, and it doesn't need to be because BalanceCheck uses the
+post-downscaling precipitation fluxes). (See also
+https://github.com/ESCOMP/ctsm/issues/201#issuecomment-444264954 .)
+
+CTSM Master Tag This Corresponds To: N/A
+
+   At least for now, we are bringing this to the release branch but not to
+   master. Here is an excerpt from the email explaining this rationale:
+
+   My question is: Should I do this:
+
+   (1) Just on a branch off of the release-clm5.0 branch, with no plan to
+       bring it back to release-clm5.0 or master
+
+   (2) On the release-clm5.0 branch, but not bring it back to master
+
+   (3) On the release-clm5.0 branch and master
+
+   My inclination right now is towards (2). I don't really like (1) because
+   this change will be wanted for a number of CMIP6-related experiments,
+   and it feels like it could be a pain to keep this branch up-to-date with
+   the evolving release-clm5.0 branch. However, the changes are going to be
+   a bit messy and having this be region-specific isn't really physically
+   justifiable (it's just being done that way to keep the climate as close
+   as possible to the official CMIP6 runs), so I'm not sure we really want
+   this on master. If we did anything on master, I could imagine having a
+   globally-applicable switch controlling this behavior, rather than having
+   it apply to just certain glacier regions.
+
+   Bette: The main reason I could see for bringing this to master is if you
+   imagine needing to use this new option in isotope-enabled runs, since
+   the isotope-enabled version of CTSM won't be on the release-clm5.0
+   branch. Do you think it's likely that you'd need to do that, or would
+   the isotope-enabled runs use the standard CMIP6 physics settings in this
+   respect?
+
+Summary of changes:
+-------------------
+
+Science changes since: release-clm5.0.14
+   None by default: just introduces a new option
+
+Software changes since: release-clm5.0.14
+   Introduces a new option, glacier_region_rain_to_snow_behavior,
+   controlling whether would-be rain-to-snow conversion ends up as snow
+   or instead ends up as liquid runoff.
+
+Changes to User Interface since: release-clm5.0.14
+   Introduces a new option, glacier_region_rain_to_snow_behavior,
+   controlling whether would-be rain-to-snow conversion ends up as snow
+   or instead ends up as liquid runoff.
+
+Testing:
+--------
+
+ [PASS means all tests PASS and OK means tests PASS other than expected fails.]
+
+  build-namelist tests:
+
+    cheyenne - ok
+
+    Tests pass, namelists differ as expected
+
+  unit-tests (components/clm/src):
+
+    cheyenne - pass
+    hobart --- not run
+
+  tools-tests (components/clm/test/tools):
+
+    cheyenne - not run
+    hobart --- not run
+
+  PTCLM testing (components/clm/tools/shared/PTCLM/test):
+
+     cheyenne - not run
+     hobart --- not run
+
+  regular tests (aux_clm):
+
+    cheyenne_intel ---- pass
+    cheyenne_gnu ------ pass
+    hobart_nag -------- pass
+    hobart_pgi -------- pass
+    hobart_intel ------ pass
+
+  regular tests (prealpha):
+
+    cheyenne_intel - not run
+    cheyenne_gnu --- not run
+    hobart_nag ----- not run
+
+  regular tests (prebeta):
+
+    cheyenne_intel - not run
+    cheyenne_gnu --- not run
+    hobart_nag ----- not run
+
+Summary of Answer changes:
+-------------------------
+
+Baseline version for comparison: release-clm5.0.14
+
+Changes answers relative to baseline: NO
+
+Detailed list of changes:
+------------------------
+
+Externals being used:
+
+   cism:   release-cesm2.0.04
+   rtm:    release-cesm2.0.02
+   mosart: release-cesm2.0.03
+   cime:   cime_cesm2_1_rel_05
+   FATES:  fates_s1.8.1_a3.0.0
+   PTCLM:  PTCLM2_180611
+
+CTSM Tag versions pulled over from master development branch: none
+
+Pull Requests that document the changes (include PR ids):
+   ESCOMP/ctsm#586 - Option for rain-to-snow to immediately run off in
+   some regions
+
+===============================================================
+===============================================================
 Tag name:  release-clm5.0.14
 Originator(s):  erik (Erik Kluzek)
 Date: Thu Nov 29 11:46:41 MST 2018
diff --git a/src/biogeophys/WaterfluxType.F90 b/src/biogeophys/WaterfluxType.F90
index 905fe9471f..849a0dd21f 100644
--- a/src/biogeophys/WaterfluxType.F90
+++ b/src/biogeophys/WaterfluxType.F90
@@ -87,6 +87,7 @@ module WaterfluxType
      real(r8), pointer :: qflx_snomelt_lyr_col     (:,:) ! col snow melt in each layer (mm H2O /s)
      real(r8), pointer :: qflx_snow_drain_col      (:)   ! col drainage from snow pack
      real(r8), pointer :: qflx_qrgwl_col           (:)   ! col qflx_surf at glaciers, wetlands, lakes
+     real(r8), pointer :: qflx_runoff_rain_to_snow_conversion_col(:) ! col runoff flux from rain-to-snow conversion, when this conversion leads to immediate runoff rather than snow (mm H2O /s)
      real(r8), pointer :: qflx_runoff_col          (:)   ! col total runoff (qflx_drain+qflx_surf+qflx_qrgwl) (mm H2O /s)
      real(r8), pointer :: qflx_runoff_r_col        (:)   ! col Rural total runoff (qflx_drain+qflx_surf+qflx_qrgwl) (mm H2O /s)
      real(r8), pointer :: qflx_runoff_u_col        (:)   ! col urban total runoff (qflx_drain+qflx_surf) (mm H2O /s) 
@@ -226,6 +227,7 @@ subroutine InitAllocate(this, bounds)
     allocate(this%qflx_snofrz_col          (begc:endc))              ; this%qflx_snofrz_col          (:)   = nan
     allocate(this%qflx_snofrz_lyr_col      (begc:endc,-nlevsno+1:0)) ; this%qflx_snofrz_lyr_col      (:,:) = nan
     allocate(this%qflx_qrgwl_col           (begc:endc))              ; this%qflx_qrgwl_col           (:)   = nan
+    allocate(this%qflx_runoff_rain_to_snow_conversion_col(begc:endc)); this%qflx_runoff_rain_to_snow_conversion_col(:) = nan
     allocate(this%qflx_drain_perched_col   (begc:endc))              ; this%qflx_drain_perched_col   (:)   = nan
     allocate(this%qflx_deficit_col         (begc:endc))              ; this%qflx_deficit_col         (:)   = nan
     allocate(this%qflx_floodc_col          (begc:endc))              ; this%qflx_floodc_col          (:)   = nan
@@ -299,6 +301,12 @@ subroutine InitHistory(this, bounds)
          long_name='surface runoff at glaciers (liquid only), wetlands, lakes; also includes melted ice runoff from QSNWCPICE', &
          ptr_col=this%qflx_qrgwl_col, c2l_scale_type='urbanf')
 
+    this%qflx_runoff_rain_to_snow_conversion_col(begc:endc) = spval
+    call hist_addfld1d (fname='QRUNOFF_RAIN_TO_SNOW_CONVERSION', units='mm/s', &
+         avgflag='A', &
+         long_name='liquid runoff from rain-to-snow conversion when this conversion leads to immediate runoff', &
+         ptr_col=this%qflx_runoff_rain_to_snow_conversion_col, c2l_scale_type='urbanf')
+
     this%qflx_drain_col(begc:endc) = spval
     call hist_addfld1d (fname='QDRAI',  units='mm/s',  &
          avgflag='A', long_name='sub-surface drainage', &
diff --git a/src/main/atm2lndMod.F90 b/src/main/atm2lndMod.F90
index c54ddcd12a..f6cde4d06d 100644
--- a/src/main/atm2lndMod.F90
+++ b/src/main/atm2lndMod.F90
@@ -22,6 +22,7 @@ module atm2lndMod
   use LandunitType   , only : lun                
   use ColumnType     , only : col
   use landunit_varcon, only : istice_mec
+  use glcBehaviorMod , only : glc_behavior_type
   !
   ! !PUBLIC TYPES:
   implicit none
@@ -31,17 +32,17 @@ module atm2lndMod
   ! !PUBLIC MEMBER FUNCTIONS:
   public :: downscale_forcings           ! Downscale atm forcing fields from gridcell to column
 
-  ! The following routines are public for the sake of unit testing; they should not be
+  ! The following routine is public for the sake of unit testing; it should not be
   ! called by production code outside this module
-  public :: partition_precip              ! Partition precipitation into rain/snow
-  public :: sens_heat_from_precip_conversion  ! Compute sensible heat flux needed to compensate for rain-snow conversion
+  public :: partition_precip             ! Partition precipitation into rain/snow
   !
   ! !PRIVATE MEMBER FUNCTIONS:
-  private :: rhos  ! calculate atmospheric density
-  private :: repartition_rain_snow_one_col ! Re-partition precipitation for a single column
-  private :: downscale_longwave          ! Downscale longwave radiation from gridcell to column
-  private :: build_normalization         ! Compute normalization factors so that downscaled fields are conservative
-  private :: check_downscale_consistency ! Check consistency of downscaling
+  private :: rhos                             ! calculate atmospheric density
+  private :: repartition_rain_snow_one_col    ! Re-partition precipitation for a single column
+  private :: sens_heat_from_precip_conversion ! Compute sensible heat flux needed to compensate for rain-snow conversion
+  private :: downscale_longwave               ! Downscale longwave radiation from gridcell to column
+  private :: build_normalization              ! Compute normalization factors so that downscaled fields are conservative
+  private :: check_downscale_consistency      ! Check consistency of downscaling
 
   character(len=*), parameter, private :: sourcefile = &
        __FILE__
@@ -51,7 +52,8 @@ module atm2lndMod
 
   !-----------------------------------------------------------------------
   subroutine downscale_forcings(bounds, &
-       topo_inst, atm2lnd_inst, eflx_sh_precip_conversion)
+       topo_inst, glc_behavior, atm2lnd_inst, &
+       eflx_sh_precip_conversion, qflx_runoff_rain_to_snow_conversion)
     !
     ! !DESCRIPTION:
     ! Downscale atmospheric forcing fields from gridcell to column.
@@ -76,8 +78,10 @@ subroutine downscale_forcings(bounds, &
     ! !ARGUMENTS:
     type(bounds_type)  , intent(in)    :: bounds  
     class(topo_type)   , intent(in)    :: topo_inst
+    type(glc_behavior_type), intent(in) :: glc_behavior
     type(atm2lnd_type) , intent(inout) :: atm2lnd_inst
     real(r8)           , intent(out)   :: eflx_sh_precip_conversion(bounds%begc:) ! sensible heat flux from precipitation conversion (W/m**2) [+ to atm]
+    real(r8)           , intent(inout) :: qflx_runoff_rain_to_snow_conversion(bounds%begc:) ! runoff flux from rain-to-snow conversion, when this conversion leads to immediate runoff rather than snow (mm H2O /s)
     !
     ! !LOCAL VARIABLES:
     integer :: g, l, c, fc         ! indices
@@ -96,6 +100,7 @@ subroutine downscale_forcings(bounds, &
     !-----------------------------------------------------------------------
 
     SHR_ASSERT_ALL((ubound(eflx_sh_precip_conversion) == (/bounds%endc/)), errMsg(sourcefile, __LINE__))
+    SHR_ASSERT_ALL((ubound(qflx_runoff_rain_to_snow_conversion) == [bounds%endc]), errMsg(sourcefile, __LINE__))
 
     associate(&
          ! Parameters:
@@ -207,8 +212,9 @@ subroutine downscale_forcings(bounds, &
 
       end do
 
-      call partition_precip(bounds, atm2lnd_inst, &
-           eflx_sh_precip_conversion(bounds%begc:bounds%endc))
+      call partition_precip(bounds, glc_behavior, atm2lnd_inst, &
+           eflx_sh_precip_conversion(bounds%begc:bounds%endc), &
+           qflx_runoff_rain_to_snow_conversion(bounds%begc:bounds%endc))
 
       call downscale_longwave(bounds, downscale_filter_c, topo_inst, atm2lnd_inst)
 
@@ -245,7 +251,8 @@ pure function rhos(qbot, pbot, tbot)
   end function rhos
 
   !-----------------------------------------------------------------------
-  subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
+  subroutine partition_precip(bounds, glc_behavior, atm2lnd_inst, &
+       eflx_sh_precip_conversion, qflx_runoff_rain_to_snow_conversion)
     !
     ! !DESCRIPTION:
     ! Partition precipitation into rain/snow based on temperature.
@@ -254,9 +261,11 @@ subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
     ! all points - not just those within the downscale filter.
     !
     ! !ARGUMENTS:
-    type(bounds_type)  , intent(in)    :: bounds  
+    type(bounds_type)  , intent(in)    :: bounds
+    type(glc_behavior_type), intent(in) :: glc_behavior
     type(atm2lnd_type) , intent(inout) :: atm2lnd_inst
     real(r8), intent(inout) :: eflx_sh_precip_conversion(bounds%begc:) ! sensible heat flux from precipitation conversion (W/m**2) [+ to atm]
+    real(r8)           , intent(inout) :: qflx_runoff_rain_to_snow_conversion(bounds%begc:) ! runoff flux from rain-to-snow conversion, when this conversion leads to immediate runoff rather than snow (mm H2O /s)
     !
     ! !LOCAL VARIABLES:
     integer  :: c,l,g      ! indices
@@ -269,6 +278,7 @@ subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
     !-----------------------------------------------------------------------
 
     SHR_ASSERT_ALL((ubound(eflx_sh_precip_conversion) == (/bounds%endc/)), errMsg(sourcefile, __LINE__))
+    SHR_ASSERT_ALL((ubound(qflx_runoff_rain_to_snow_conversion) == [bounds%endc]), errMsg(sourcefile, __LINE__))
 
     associate(&
          ! Gridcell-level non-downscaled fields:
@@ -288,6 +298,7 @@ subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
           forc_rain_c(c)  = forc_rain_g(g)
           forc_snow_c(c)  = forc_snow_g(g)
           eflx_sh_precip_conversion(c) = 0._r8
+          qflx_runoff_rain_to_snow_conversion(c) = 0._r8
        end if
     end do
 
@@ -296,6 +307,7 @@ subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
        do c = bounds%begc, bounds%endc
           if (col%active(c)) then
              l = col%landunit(c)
+             g = col%gridcell(c)
              rain_old = forc_rain_c(c)
              snow_old = forc_snow_c(c)
              if (lun%itype(l) == istice_mec) then
@@ -311,11 +323,21 @@ subroutine partition_precip(bounds, atm2lnd_inst, eflx_sh_precip_conversion)
                   frac_rain_slope = frac_rain_slope, &
                   rain = forc_rain_c(c), &
                   snow = forc_snow_c(c))
+             if (glc_behavior%rain_to_snow_runs_off_grc(g)) then
+                ! Note that, despite being a flag in glc_behavior, this actually applies
+                ! to all landunits
+                if (forc_snow_c(c) > snow_old) then
+                   ! Instead of converting rain to snow, make it run off immediately
+                   qflx_runoff_rain_to_snow_conversion(c) = forc_snow_c(c) - snow_old
+                   forc_snow_c(c) = snow_old
+                end if
+             end if
              call sens_heat_from_precip_conversion(&
                   rain_old = rain_old, &
                   snow_old = snow_old, &
                   rain_new = forc_rain_c(c), &
                   snow_new = forc_snow_c(c), &
+                  rain_to_snow_runoff = qflx_runoff_rain_to_snow_conversion(c), &
                   sens_heat_flux = eflx_sh_precip_conversion(c))
           end if
        end do
@@ -361,7 +383,7 @@ end subroutine repartition_rain_snow_one_col
 
   !-----------------------------------------------------------------------
   subroutine sens_heat_from_precip_conversion(rain_old, snow_old, rain_new, snow_new, &
-       sens_heat_flux)
+       rain_to_snow_runoff, sens_heat_flux)
     !
     ! !DESCRIPTION:
     ! Given old and new rain and snow amounts, compute the sensible heat flux needed to
@@ -374,6 +396,7 @@ subroutine sens_heat_from_precip_conversion(rain_old, snow_old, rain_new, snow_n
     real(r8), intent(in)  :: snow_old        ! [(mm water equivalent)/s]
     real(r8), intent(in)  :: rain_new        ! [mm/s]
     real(r8), intent(in)  :: snow_new        ! [(mm water equivalent)/s]
+    real(r8), intent(in)  :: rain_to_snow_runoff ! rain that, rather than being converted to snow, instead immediately runs off [mm/s]
     real(r8), intent(out) :: sens_heat_flux  ! [W/m^2]
     !
     ! !LOCAL VARIABLES:
@@ -388,10 +411,18 @@ subroutine sens_heat_from_precip_conversion(rain_old, snow_old, rain_new, snow_n
     !-----------------------------------------------------------------------
 
     total_old = rain_old + snow_old
-    total_new = rain_new + snow_new
+    total_new = rain_new + snow_new + rain_to_snow_runoff
     SHR_ASSERT(abs(total_new - total_old) <= (tol * total_old), subname//' ERROR: mismatch between old and new totals')
 
-    ! rain to snow releases energy, so results in a positive heat flux to atm
+    ! Rain to snow releases energy, so results in a positive heat flux to atm.
+    !
+    ! While perhaps not immediately obvious, we can calculate the energy flux entirely
+    ! based on the change in snow. This is because there are three possible conversions:
+    ! (1) snow to rain, (2) rain to snow, and (3) rain to runoff. (1) and (2) have a
+    ! change in rain that is exactly opposite the change in snow (so the difference in
+    ! snow is all we need to know); (3) doesn't result in any change in snow and also
+    ! doesn't result in any necessary heat flux, so just considering the change in snow
+    ! is again correct.
     rain_to_snow = snow_new - snow_old
     sens_heat_flux = rain_to_snow * mm_to_m * denh2o * hfus
 
diff --git a/src/main/clm_driver.F90 b/src/main/clm_driver.F90
index c66112c0bc..8f6e372090 100644
--- a/src/main/clm_driver.F90
+++ b/src/main/clm_driver.F90
@@ -410,8 +410,11 @@ subroutine clm_drv(doalb, nextsw_cday, declinp1, declin, rstwr, nlend, rdate, ro
             atm_topo = atm2lnd_inst%forc_topo_grc(bounds_clump%begg:bounds_clump%endg))
 
        call downscale_forcings(bounds_clump, &
-            topo_inst, atm2lnd_inst, &
-            eflx_sh_precip_conversion = energyflux_inst%eflx_sh_precip_conversion_col(bounds_clump%begc:bounds_clump%endc))
+            topo_inst, glc_behavior, atm2lnd_inst, &
+            eflx_sh_precip_conversion = &
+            energyflux_inst%eflx_sh_precip_conversion_col(bounds_clump%begc:bounds_clump%endc), &
+            qflx_runoff_rain_to_snow_conversion = &
+            waterflux_inst%qflx_runoff_rain_to_snow_conversion_col(bounds_clump%begc:bounds_clump%endc))
 
        ! Update filters that depend on variables set in clm_drv_init
        
diff --git a/src/main/glcBehaviorMod.F90 b/src/main/glcBehaviorMod.F90
index 6240567937..9cc8276cef 100644
--- a/src/main/glcBehaviorMod.F90
+++ b/src/main/glcBehaviorMod.F90
@@ -83,6 +83,13 @@ module glcBehaviorMod
      ! sent to the river model as ice (a crude parameterization of iceberg calving).
      logical, allocatable, public :: ice_runoff_melted_grc(:)
 
+     ! If rain_to_snow_runs_off_grc(g) is true, then any rain that would be converted to
+     ! snow through precipitation repartitioning/downscaling instead runs off immediately.
+     !
+     ! Note that, unlike the other options here, this applies to ALL landunits in the
+     ! given region, so that the physics are consistent between different landunit types.
+     logical, allocatable, public :: rain_to_snow_runs_off_grc(:)
+
      ! ------------------------------------------------------------------------
      ! Private data
      ! ------------------------------------------------------------------------
@@ -163,8 +170,8 @@ module glcBehaviorMod
 
   ! !PRIVATE MEMBER DATA:
 
-  ! Longest name allowed for glacier_region_behavior, glacier_region_melt_behavior and
-  ! glacier_region_ice_runoff_behavior
+  ! Longest name allowed for glacier_region_behavior, glacier_region_melt_behavior,
+  ! glacier_region_ice_runoff_behavior and glacier_region_rain_to_snow_behavior
   integer, parameter :: max_behavior_name_len = 32
 
   ! Smallest and largest allowed values for a glacier region ID
@@ -201,6 +208,7 @@ subroutine Init(this, begg, endg, NLFilename)
     character(len=max_behavior_name_len) :: glacier_region_behavior(min_glacier_region_id:max_glacier_region_id)
     character(len=max_behavior_name_len) :: glacier_region_melt_behavior(min_glacier_region_id:max_glacier_region_id)
     character(len=max_behavior_name_len) :: glacier_region_ice_runoff_behavior(min_glacier_region_id:max_glacier_region_id)
+    character(len=max_behavior_name_len) :: glacier_region_rain_to_snow_behavior(min_glacier_region_id:max_glacier_region_id)
 
     character(len=*), parameter :: subname = 'Init'
     !-----------------------------------------------------------------------
@@ -208,18 +216,20 @@ subroutine Init(this, begg, endg, NLFilename)
     allocate(glacier_region_map(begg:endg))
     call this%read_surface_dataset(begg, endg, glacier_region_map(begg:endg))
     call this%read_namelist(NLFilename, glacier_region_behavior, &
-         glacier_region_melt_behavior, glacier_region_ice_runoff_behavior)
+         glacier_region_melt_behavior, glacier_region_ice_runoff_behavior, &
+         glacier_region_rain_to_snow_behavior)
 
     call this%InitFromInputs(begg, endg, &
          glacier_region_map(begg:endg), glacier_region_behavior, &
-         glacier_region_melt_behavior, glacier_region_ice_runoff_behavior)
+         glacier_region_melt_behavior, glacier_region_ice_runoff_behavior, &
+         glacier_region_rain_to_snow_behavior)
 
   end subroutine Init
 
   !-----------------------------------------------------------------------
   subroutine InitFromInputs(this, begg, endg, &
        glacier_region_map, glacier_region_behavior_str, glacier_region_melt_behavior_str, &
-       glacier_region_ice_runoff_behavior_str)
+       glacier_region_ice_runoff_behavior_str, glacier_region_rain_to_snow_behavior_str)
     !
     ! !DESCRIPTION:
     ! Initialize a glc_behavior_type object given a map of glacier region IDs and an
@@ -261,6 +271,12 @@ subroutine InitFromInputs(this, begg, endg, &
     ! - 'melted'
     character(len=*), intent(in) :: glacier_region_ice_runoff_behavior_str(min_glacier_region_id:)
 
+    ! string giving treatment of rain-to-snow conversion for each glacier region ID
+    ! allowed values are:
+    ! - 'converted_to_snow'
+    ! - 'runs_off'
+    character(len=*), intent(in) :: glacier_region_rain_to_snow_behavior_str(min_glacier_region_id:)
+
     !
     ! !LOCAL VARIABLES:
     ! whether each glacier region ID is present in the glacier_region_map
@@ -275,11 +291,15 @@ subroutine InitFromInputs(this, begg, endg, &
     ! integer codes corresponding to glacier_region_ice_runoff_behavior_str
     integer :: glacier_region_ice_runoff_behavior(min_glacier_region_id:max_glacier_region_id)
 
+    ! integer codes corresponding to glacier_region_rain_to_snow_behavior_str
+    integer :: glacier_region_rain_to_snow_behavior(min_glacier_region_id:max_glacier_region_id)
+
     integer :: g
     integer :: my_id
     integer :: my_behavior
     integer :: my_melt_behavior
     integer :: my_ice_runoff_behavior
+    integer :: my_rain_to_snow_behavior
 
     ! possible glacier_region_behavior codes
     integer, parameter :: BEHAVIOR_MULTIPLE = 1
@@ -294,8 +314,13 @@ subroutine InitFromInputs(this, begg, endg, &
     integer, parameter :: ICE_RUNOFF_BEHAVIOR_REMAINS_ICE = 1
     integer, parameter :: ICE_RUNOFF_BEHAVIOR_MELTED = 2
 
+    ! possible glacier_region_rain_to_snow_behavior codes
+    integer, parameter :: RAIN_TO_SNOW_BEHAVIOR_CONVERTED_TO_SNOW = 1
+    integer, parameter :: RAIN_TO_SNOW_BEHAVIOR_RUNS_OFF = 2
+
     ! value indicating that a behavior code has not been set (for glacier_region_behavior,
-    ! glacier_region_melt_behavior or glacier_region_ice_runoff_behavior)
+    ! glacier_region_melt_behavior, glacier_region_ice_runoff_behavior, or
+    ! glacier_region_rain_to_snow_behavior)
     integer, parameter :: BEHAVIOR_UNSET = -1
 
     character(len=*), parameter :: subname = 'InitFromInputs'
@@ -310,6 +335,7 @@ subroutine InitFromInputs(this, begg, endg, &
     call translate_glacier_region_behavior
     call translate_glacier_region_melt_behavior
     call translate_glacier_region_ice_runoff_behavior
+    call translate_glacier_region_rain_to_snow_behavior
 
     call this%InitAllocate(begg, endg)
 
@@ -318,11 +344,13 @@ subroutine InitFromInputs(this, begg, endg, &
        my_behavior = glacier_region_behavior(my_id)
        my_melt_behavior = glacier_region_melt_behavior(my_id)
        my_ice_runoff_behavior = glacier_region_ice_runoff_behavior(my_id)
+       my_rain_to_snow_behavior = glacier_region_rain_to_snow_behavior(my_id)
 
        ! This should only happen due to a programming error, not due to a user input error
        SHR_ASSERT(my_behavior /= BEHAVIOR_UNSET, errMsg(sourcefile, __LINE__))
        SHR_ASSERT(my_melt_behavior /= BEHAVIOR_UNSET, errMsg(sourcefile, __LINE__))
        SHR_ASSERT(my_ice_runoff_behavior /= BEHAVIOR_UNSET, errMsg(sourcefile, __LINE__))
+       SHR_ASSERT(my_rain_to_snow_behavior /= BEHAVIOR_UNSET, errMsg(sourcefile, __LINE__))
 
        if (my_behavior == BEHAVIOR_VIRTUAL) then
           this%has_virtual_columns_grc(g) = .true.
@@ -342,6 +370,12 @@ subroutine InitFromInputs(this, begg, endg, &
           this%ice_runoff_melted_grc(g) = .false.
        end if
 
+       if (my_rain_to_snow_behavior == RAIN_TO_SNOW_BEHAVIOR_RUNS_OFF) then
+          this%rain_to_snow_runs_off_grc(g) = .true.
+       else
+          this%rain_to_snow_runs_off_grc(g) = .false.
+       end if
+
        ! For now, allow_multiple_columns_grc is simply the opposite of
        ! collapse_to_atm_topo_grc. However, we maintain the separate
        ! allow_multiple_columns_grc so that the public interface can stay the same if we
@@ -481,16 +515,45 @@ subroutine translate_glacier_region_ice_runoff_behavior
       end do
     end subroutine translate_glacier_region_ice_runoff_behavior
 
+    subroutine translate_glacier_region_rain_to_snow_behavior
+      integer :: i
+
+      do i = min_glacier_region_id, max_glacier_region_id
+         glacier_region_rain_to_snow_behavior(i) = BEHAVIOR_UNSET
+
+         if (glacier_region_present(i)) then
+            SHR_ASSERT_ALL((ubound(glacier_region_rain_to_snow_behavior_str) >= [i]), errMsg(sourcefile, __LINE__))
+
+            select case (glacier_region_rain_to_snow_behavior_str(i))
+            case ('converted_to_snow')
+               glacier_region_rain_to_snow_behavior(i) = RAIN_TO_SNOW_BEHAVIOR_CONVERTED_TO_SNOW
+            case ('runs_off')
+               glacier_region_rain_to_snow_behavior(i) = RAIN_TO_SNOW_BEHAVIOR_RUNS_OFF
+            case (behavior_str_unset)
+               write(iulog,*) ' ERROR: glacier_region_rain_to_snow_behavior not specified for ID ', i
+               write(iulog,*) 'You probably need to extend the glacier_region_rain_to_snow_behavior namelist array'
+               call endrun(msg=' ERROR: glacier_region_rain_to_snow_behavior not specified for ID '// &
+                    errMsg(sourcefile, __LINE__))
+            case default
+               write(iulog,*) ' ERROR: Unknown glacier_region_rain_to_snow_behavior for ID ', i
+               write(iulog,*) glacier_region_rain_to_snow_behavior_str(i)
+               write(iulog,*) 'Allowable values are: converted_to_snow, runs_off'
+               call endrun(msg=' ERROR: Unknown glacier_region_rain_to_snow_behavior'// &
+                    errMsg(sourcefile, __LINE__))
+            end select
+         end if
+      end do
+    end subroutine translate_glacier_region_rain_to_snow_behavior
+
   end subroutine InitFromInputs
 
 
   !-----------------------------------------------------------------------
   subroutine InitSetDirectly(this, begg, endg, &
-       has_virtual_columns, collapse_to_atm_topo)
+       has_virtual_columns, collapse_to_atm_topo, rain_to_snow_runs_off)
     !
     ! !DESCRIPTION:
-    ! Initialize a glc_behavior_type object by directly setting has_virtual_columns and
-    ! collapse_to_atm_topo
+    ! Initialize a glc_behavior_type object by directly setting provided fields
     !
     ! This version is meant for testing
     !
@@ -500,20 +563,35 @@ subroutine InitSetDirectly(this, begg, endg, &
     class(glc_behavior_type), intent(inout) :: this
     integer, intent(in) :: begg  ! beginning gridcell index
     integer, intent(in) :: endg  ! ending gridcell index
-    logical, intent(in) :: has_virtual_columns(begg:)
-    logical, intent(in) :: collapse_to_atm_topo(begg:)
+    logical, intent(in), optional :: has_virtual_columns(begg:)
+    logical, intent(in), optional :: collapse_to_atm_topo(begg:)
+    logical, intent(in), optional :: rain_to_snow_runs_off(begg:)
     !
     ! !LOCAL VARIABLES:
 
     character(len=*), parameter :: subname = 'InitForTesting'
     !-----------------------------------------------------------------------
 
-    SHR_ASSERT_ALL((ubound(has_virtual_columns) == (/endg/)), errMsg(sourcefile, __LINE__))
-    SHR_ASSERT_ALL((ubound(collapse_to_atm_topo) == (/endg/)), errMsg(sourcefile, __LINE__))
+    if (present(has_virtual_columns)) then
+       SHR_ASSERT_ALL((ubound(has_virtual_columns) == (/endg/)), errMsg(sourcefile, __LINE__))
+    end if
+    if (present(collapse_to_atm_topo)) then
+       SHR_ASSERT_ALL((ubound(collapse_to_atm_topo) == (/endg/)), errMsg(sourcefile, __LINE__))
+    end if
+    if (present(rain_to_snow_runs_off)) then
+       SHR_ASSERT_ALL((ubound(rain_to_snow_runs_off) == [endg]), errMsg(sourcefile, __LINE__))
+    end if
 
     call this%InitAllocate(begg, endg)
-    this%has_virtual_columns_grc(:) = has_virtual_columns(:)
-    this%collapse_to_atm_topo_grc(:) = collapse_to_atm_topo(:)
+    if (present(has_virtual_columns)) then
+       this%has_virtual_columns_grc(:) = has_virtual_columns(:)
+    end if
+    if (present(collapse_to_atm_topo)) then
+       this%collapse_to_atm_topo_grc(:) = collapse_to_atm_topo(:)
+    end if
+    if (present(rain_to_snow_runs_off)) then
+       this%rain_to_snow_runs_off_grc(:) = rain_to_snow_runs_off(:)
+    end if
 
   end subroutine InitSetDirectly
 
@@ -539,6 +617,7 @@ subroutine InitAllocate(this, begg, endg)
     allocate(this%melt_replaced_by_ice_grc(begg:endg)); this%melt_replaced_by_ice_grc(:) = .false.
     allocate(this%collapse_to_atm_topo_grc(begg:endg)); this%collapse_to_atm_topo_grc(:) = .false.
     allocate(this%ice_runoff_melted_grc(begg:endg)); this%ice_runoff_melted_grc(:) = .false.
+    allocate(this%rain_to_snow_runs_off_grc(begg:endg)); this%rain_to_snow_runs_off_grc(:) = .false.
 
   end subroutine InitAllocate
 
@@ -590,7 +669,8 @@ end subroutine read_surface_dataset
 
   !-----------------------------------------------------------------------
   subroutine read_namelist(NLFilename, glacier_region_behavior, &
-       glacier_region_melt_behavior, glacier_region_ice_runoff_behavior)
+       glacier_region_melt_behavior, glacier_region_ice_runoff_behavior, &
+       glacier_region_rain_to_snow_behavior)
     !
     ! !DESCRIPTION:
     ! Read local namelist items
@@ -610,6 +690,8 @@ subroutine read_namelist(NLFilename, glacier_region_behavior, &
          glacier_region_melt_behavior(min_glacier_region_id:max_glacier_region_id)
     character(len=max_behavior_name_len), intent(out) :: &
          glacier_region_ice_runoff_behavior(min_glacier_region_id:max_glacier_region_id)
+    character(len=max_behavior_name_len), intent(out) :: &
+         glacier_region_rain_to_snow_behavior(min_glacier_region_id:max_glacier_region_id)
     !
     ! !LOCAL VARIABLES:
     integer :: unitn     ! unit for namelist file
@@ -620,12 +702,13 @@ subroutine read_namelist(NLFilename, glacier_region_behavior, &
 
     namelist /clm_glacier_behavior/ &
          glacier_region_behavior, glacier_region_melt_behavior, &
-         glacier_region_ice_runoff_behavior
+         glacier_region_ice_runoff_behavior, glacier_region_rain_to_snow_behavior
 
     ! Initialize options to default values
     glacier_region_behavior(:) = behavior_str_unset
     glacier_region_melt_behavior(:) = behavior_str_unset
     glacier_region_ice_runoff_behavior(:) = behavior_str_unset
+    glacier_region_rain_to_snow_behavior(:) = behavior_str_unset
 
     if (masterproc) then
        unitn = getavu()
@@ -647,6 +730,7 @@ subroutine read_namelist(NLFilename, glacier_region_behavior, &
     call shr_mpi_bcast(glacier_region_behavior, mpicom)
     call shr_mpi_bcast(glacier_region_melt_behavior, mpicom)
     call shr_mpi_bcast(glacier_region_ice_runoff_behavior, mpicom)
+    call shr_mpi_bcast(glacier_region_rain_to_snow_behavior, mpicom)
 
     if (masterproc) then
        write(iulog,*) ' '
diff --git a/src/main/lnd2atmMod.F90 b/src/main/lnd2atmMod.F90
index 2a4a00d5cd..5ef55973b1 100644
--- a/src/main/lnd2atmMod.F90
+++ b/src/main/lnd2atmMod.F90
@@ -338,10 +338,20 @@ subroutine lnd2atm(bounds, &
           waterflux_inst%qflx_qrgwl_col(c) = waterflux_inst%qflx_qrgwl_col(c) + &
                lnd2atm_inst%qflx_liq_from_ice_col(c)
 
+          ! NOTE(wjs, 2018-12-05) Similarly, it's not entirely appropriate to put
+          ! qflx_runoff_rain_to_snow_conversion_col into qflx_qrgwl_col, since again, this
+          ! is generated over landunits other than glaciers, wetlands and lakes. I'm
+          ! putting it in qflx_qrgwl_col partly because glacier landunits are typically
+          ! the primary source of this flux, and partly just because I'm not sure where
+          ! else to put it.
+          waterflux_inst%qflx_qrgwl_col(c) = waterflux_inst%qflx_qrgwl_col(c) + &
+               waterflux_inst%qflx_runoff_rain_to_snow_conversion_col(c)
+
           ! qflx_runoff is the sum of a number of terms, including qflx_qrgwl. Since we
           ! are adjusting qflx_qrgwl above, we need to adjust qflx_runoff analogously.
           waterflux_inst%qflx_runoff_col(c) = waterflux_inst%qflx_runoff_col(c) + &
-               lnd2atm_inst%qflx_liq_from_ice_col(c)
+               lnd2atm_inst%qflx_liq_from_ice_col(c) + &
+               waterflux_inst%qflx_runoff_rain_to_snow_conversion_col(c)
        end if
     end do
 
diff --git a/src/main/test/atm2lnd_test/CMakeLists.txt b/src/main/test/atm2lnd_test/CMakeLists.txt
index 018b875a27..e42192b45b 100644
--- a/src/main/test/atm2lnd_test/CMakeLists.txt
+++ b/src/main/test/atm2lnd_test/CMakeLists.txt
@@ -1,7 +1,6 @@
 set(pfunit_sources
   test_downscale_forcings.pf
-  test_partition_precip.pf
-  test_sens_heat_from_precip_conversion.pf)
+  test_partition_precip.pf)
 
 create_pFUnit_test(atm2lnd test_atm2lnd_exe
   "${pfunit_sources}" "")
diff --git a/src/main/test/atm2lnd_test/test_downscale_forcings.pf b/src/main/test/atm2lnd_test/test_downscale_forcings.pf
index 4fe5621c7b..1b60286543 100644
--- a/src/main/test/atm2lnd_test/test_downscale_forcings.pf
+++ b/src/main/test/atm2lnd_test/test_downscale_forcings.pf
@@ -11,6 +11,7 @@ module test_downscale_forcings
   use atm2lndType, only : atm2lnd_type, atm2lnd_params_type
   use TopoMod, only : topo_type
   use decompMod, only : bounds_type
+  use glcBehaviorMod, only : glc_behavior_type
   use filterColMod
 
   implicit none
@@ -24,7 +25,9 @@ module test_downscale_forcings
   type, extends(TestCase) :: TestDownscaleForcings
      type(atm2lnd_type) :: atm2lnd_inst
      type(topo_type_always_downscale) :: topo_inst
+     type(glc_behavior_type) :: glc_behavior
      real(r8), allocatable :: eflx_sh_precip_conversion(:)
+     real(r8), allocatable :: rain_to_snow_runoff(:)
    contains
      procedure :: setUp
      procedure :: tearDown
@@ -194,12 +197,16 @@ contains
   subroutine call_downscale_forcings(this)
     ! Wraps the call to downscale_forcings
     !
-    ! Modifies this%atm2lnd_inst and this%eflx_sh_precip_conversion
+    ! Modifies this%atm2lnd_inst, this%eflx_sh_precip_conversion, and this%rain_to_snow_runoff
     class(TestDownscaleForcings), intent(inout) :: this
 
     this%eflx_sh_precip_conversion = col_array()
-    call downscale_forcings(bounds, this%topo_inst, this%atm2lnd_inst, &
-         this%eflx_sh_precip_conversion)
+    this%rain_to_snow_runoff = col_array()
+    call this%glc_behavior%InitSetDirectly( &
+         begg = bounds%begg, &
+         endg = bounds%endg)
+    call downscale_forcings(bounds, this%topo_inst, this%glc_behavior, this%atm2lnd_inst, &
+         this%eflx_sh_precip_conversion, this%rain_to_snow_runoff)
   end subroutine call_downscale_forcings
 
   ! ========================================================================
diff --git a/src/main/test/atm2lnd_test/test_partition_precip.pf b/src/main/test/atm2lnd_test/test_partition_precip.pf
index 4e996988d0..a66e57b805 100644
--- a/src/main/test/atm2lnd_test/test_partition_precip.pf
+++ b/src/main/test/atm2lnd_test/test_partition_precip.pf
@@ -5,6 +5,7 @@ module test_partition_precip
   use pfunit_mod
   use atm2lndMod
   use atm2lndType
+  use glcBehaviorMod, only : glc_behavior_type
   use shr_kind_mod, only : r8 => shr_kind_r8
   use unittestSubgridMod
   use unittestSimpleSubgridSetupsMod
@@ -19,11 +20,14 @@ module test_partition_precip
   @TestCase
   type, extends(TestCase) :: TestPartitionPrecip
      type(atm2lnd_type) :: atm2lnd_inst
+     type(glc_behavior_type) :: glc_behavior
      real(r8), allocatable :: sh_from_conversion(:)
+     real(r8), allocatable :: rain_to_snow_runoff(:)
    contains
      procedure :: setUp
      procedure :: tearDown
      procedure :: set_inputs
+     procedure :: call_partition_precip
   end type TestPartitionPrecip
 
   real(r8), parameter :: tol = 1.e-13
@@ -48,7 +52,8 @@ contains
     call unittest_subgrid_teardown()
   end subroutine tearDown
 
-  subroutine set_inputs(this, rain, snow, temperature, repartition_rain_snow)
+  subroutine set_inputs(this, rain, snow, temperature, &
+       repartition_rain_snow, rain_to_snow_runs_off)
     ! set necessary input variables
     class(TestPartitionPrecip), intent(inout) :: this
     real(r8), intent(in) :: rain(:)
@@ -58,7 +63,11 @@ contains
     ! If not provided, set to true
     logical, intent(in), optional :: repartition_rain_snow
 
+    ! If provided, this should be a gridcell-level array; if not provided, set to false
+    logical, intent(in), optional :: rain_to_snow_runs_off(bounds%begg:)
+
     logical :: l_repartition_rain_snow
+    logical :: l_rain_to_snow_runs_off(bounds%begg:bounds%endg)
     type(atm2lnd_params_type) :: atm2lnd_params
 
     if (present(repartition_rain_snow)) then
@@ -67,6 +76,13 @@ contains
        l_repartition_rain_snow = .true.
     end if
 
+    if (present(rain_to_snow_runs_off)) then
+       @assertEqual([bounds%endg], ubound(rain_to_snow_runs_off))
+       l_rain_to_snow_runs_off(:) = rain_to_snow_runs_off(:)
+    else
+       l_rain_to_snow_runs_off(:) = .false.
+    end if
+
     atm2lnd_params = atm2lnd_params_type( &
          repartition_rain_snow = l_repartition_rain_snow, &
          glcmec_downscale_longwave = .false., &
@@ -77,8 +93,13 @@ contains
          precip_repartition_nonglc_all_rain_t = precip_repartition_nonglc_all_rain_t)
 
     ! Allocate necessary variables
+    call this%glc_behavior%InitSetDirectly( &
+         begg = bounds%begg, &
+         endg = bounds%endg, &
+         rain_to_snow_runs_off = l_rain_to_snow_runs_off)
     call this%atm2lnd_inst%InitForTesting(bounds, atm2lnd_params)
     this%sh_from_conversion = col_array()
+    this%rain_to_snow_runoff = col_array()
 
     ! set input variables
     this%atm2lnd_inst%forc_rain_not_downscaled_grc(bounds%begg:bounds%endg) = rain(:)
@@ -86,6 +107,14 @@ contains
     this%atm2lnd_inst%forc_t_downscaled_col(bounds%begc:bounds%endc) = temperature(:)
   end subroutine set_inputs
 
+  subroutine call_partition_precip(this)
+    class(TestPartitionPrecip), intent(inout) :: this
+
+    call partition_precip(bounds, this%glc_behavior, this%atm2lnd_inst, &
+         eflx_sh_precip_conversion = this%sh_from_conversion, &
+         qflx_runoff_rain_to_snow_conversion = this%rain_to_snow_runoff)
+  end subroutine call_partition_precip
+
   @Test
   subroutine lowTemp_resultsInCorrectPartitioning(this)
     class(TestPartitionPrecip), intent(inout) :: this
@@ -93,13 +122,14 @@ contains
     call setup_single_veg_patch(pft_type=1)
     call this%set_inputs(rain=[1._r8], snow=[2._r8], temperature=[270._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
          snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
     @assertEqual(0._r8, rain_col(begc), tolerance=tol)
     @assertEqual(3._r8, snow_col(begc), tolerance=tol)
+    @assertEqual([0._r8], this%rain_to_snow_runoff)
     end associate
   end subroutine lowTemp_resultsInCorrectPartitioning
 
@@ -110,32 +140,51 @@ contains
     call setup_single_veg_patch(pft_type=1)
     call this%set_inputs(rain=[1._r8], snow=[2._r8], temperature=[276._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
          snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
     @assertEqual(3._r8, rain_col(begc), tolerance=tol)
     @assertEqual(0._r8, snow_col(begc), tolerance=tol)
+    @assertEqual([0._r8], this%rain_to_snow_runoff)
     end associate
   end subroutine highTemp_resultsInCorrectPartitioning
 
   @Test
-  subroutine intermediateTemp_resultsInCorrectPartitioning(this)
+  subroutine intermediateTemp_resultsInCorrectPartitioningAndHeatFlux(this)
+    ! Unlike other tests, where we check for either correct partitioning or correct heat
+    ! flux in a given test: This test checks both for convenience (to avoid duplication
+    ! between two tests which would require us to update both of them if the ramp for
+    ! rain-snow conversion changed).
     class(TestPartitionPrecip), intent(inout) :: this
+    real(r8), parameter :: rain_orig = 1._r8
+    real(r8), parameter :: snow_orig = 2._r8
+    real(r8) :: tot_precip
+    real(r8) :: expected_rain
+    real(r8) :: expected_snow
+    real(r8) :: expected_heat_flux
 
     call setup_single_veg_patch(pft_type=1)
-    call this%set_inputs(rain=[1._r8], snow=[2._r8], temperature=[SHR_CONST_TKFRZ + 1.5_r8])
+    call this%set_inputs(rain=[rain_orig], snow=[snow_orig], temperature=[SHR_CONST_TKFRZ + 1.5_r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
          snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
-    @assertEqual(3._r8 * 0.75_r8, rain_col(begc), tolerance=tol)
-    @assertEqual(3._r8 * 0.25_r8, snow_col(begc), tolerance=tol)
+    tot_precip = rain_orig + snow_orig
+    expected_rain = tot_precip * 0.75_r8
+    expected_snow = tot_precip * 0.25_r8
+    @assertEqual(expected_rain, rain_col(begc), tolerance=tol)
+    @assertEqual(expected_snow, snow_col(begc), tolerance=tol)
+    @assertEqual([0._r8], this%rain_to_snow_runoff)
+
+    ! Snow to rain extracts energy, so results in a negative heat flux to atm
+    expected_heat_flux = (rain_orig - expected_rain) * mm_to_m * denh2o * hfus
+    @assertEqual([expected_heat_flux], this%sh_from_conversion, tolerance=tol)
     end associate
-  end subroutine intermediateTemp_resultsInCorrectPartitioning
+  end subroutine intermediateTemp_resultsInCorrectPartitioningAndHeatFlux
 
   @Test
   subroutine intermediateTemp_glacier_resultsInCorrectPartitioning(this)
@@ -150,13 +199,14 @@ contains
     ! Choose a temperature 3/4 of the way from all-snow to all-rain
     call this%set_inputs(rain=[1._r8], snow=[2._r8], temperature=[SHR_CONST_TKFRZ - 3._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
          snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
     @assertEqual(3._r8 * 0.75_r8, rain_col(begc), tolerance=tol)
     @assertEqual(3._r8 * 0.25_r8, snow_col(begc), tolerance=tol)
+    @assertEqual([0._r8], this%rain_to_snow_runoff)
     end associate
   end subroutine intermediateTemp_glacier_resultsInCorrectPartitioning
 
@@ -167,7 +217,7 @@ contains
     call setup_single_veg_patch(pft_type=1)
     call this%set_inputs(rain=[5._r8], snow=[0._r8], temperature=[290._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     @assertEqual([0._r8], this%sh_from_conversion)
   end subroutine noConversion_resultsInNoHeatFlux
@@ -181,7 +231,7 @@ contains
     call setup_single_veg_patch(pft_type=1)
     call this%set_inputs(rain=[2._r8], snow=[snow_old], temperature=[290._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     ! Snow to rain extracts energy, so results in a negative heat flux to atm
     expected = -1._r8 * snow_old * mm_to_m * denh2o * hfus
@@ -197,13 +247,54 @@ contains
     call setup_single_veg_patch(pft_type=1)
     call this%set_inputs(rain=[rain_old], snow=[3._r8], temperature=[250._r8])
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     ! Rain to snow releases energy, so results in a positive heat flux to atm
     expected = rain_old * mm_to_m * denh2o * hfus
     @assertEqual([expected], this%sh_from_conversion, tolerance=tol)
   end subroutine rainToSnow_resultsInCorrectHeatFlux
 
+  @Test
+  subroutine lowTemp_glcBehaviorRunsOff_resultsInCorrectChanges(this)
+    class(TestPartitionPrecip), intent(inout) :: this
+
+    call setup_single_veg_patch(pft_type=1)
+    call this%set_inputs(rain=[2._r8], snow=[3._r8], temperature=[250._r8], &
+         rain_to_snow_runs_off=[.true.])
+
+    call this%call_partition_precip()
+
+    associate(&
+         rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
+         snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
+    @assertEqual([0._r8], rain_col, tolerance=tol)
+    @assertEqual([3._r8], snow_col, tolerance=tol)
+    @assertEqual([2._r8], this%rain_to_snow_runoff, tolerance=tol)
+    @assertEqual([0._r8], this%sh_from_conversion)
+    end associate
+  end subroutine lowTemp_glcBehaviorRunsOff_resultsInCorrectChanges
+
+  @Test
+  subroutine highTemp_glcBehaviorRunsOff_resultsInCorrectPartitioning(this)
+    ! The partitioning in this case should be the same as if we were using the default
+    ! glc behavior
+    class(TestPartitionPrecip), intent(inout) :: this
+
+    call setup_single_veg_patch(pft_type=1)
+    call this%set_inputs(rain=[2._r8], snow=[3._r8], temperature=[290._r8], &
+         rain_to_snow_runs_off=[.true.])
+
+    call this%call_partition_precip()
+
+    associate(&
+         rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
+         snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
+    @assertEqual([5._r8], rain_col, tolerance=tol)
+    @assertEqual([0._r8], snow_col, tolerance=tol)
+    @assertEqual([0._r8], this%rain_to_snow_runoff, tolerance=tol)
+    end associate
+  end subroutine highTemp_glcBehaviorRunsOff_resultsInCorrectPartitioning
+
   @Test
   subroutine repartitionFlagFalse_resultsInNoChange(this)
     class(TestPartitionPrecip), intent(inout) :: this
@@ -212,7 +303,7 @@ contains
     call this%set_inputs(rain=[1._r8], snow=[2._r8], temperature=[250._r8], &
          repartition_rain_snow = .false.)
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
@@ -220,6 +311,7 @@ contains
     @assertEqual([1._r8], rain_col)
     @assertEqual([2._r8], snow_col)
     @assertEqual([0._r8], this%sh_from_conversion)
+    @assertEqual([0._r8], this%rain_to_snow_runoff)
     end associate
   end subroutine repartitionFlagFalse_resultsInNoChange
 
@@ -235,13 +327,14 @@ contains
     call setup_ncells_single_veg_patch(ncells=2, pft_type=1)
     call this%set_inputs(rain=rain, snow=snow, temperature=temp)
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     associate(&
          rain_col => this%atm2lnd_inst%forc_rain_downscaled_col, &
          snow_col => this%atm2lnd_inst%forc_snow_downscaled_col)
     @assertEqual(rain_expected, rain_col, tolerance=tol)
     @assertEqual(snow_expected, snow_col, tolerance=tol)
+    @assertEqual([0._r8, 0._r8], this%rain_to_snow_runoff)
     end associate
 
   end subroutine multiPoint_resultsInCorrectPartitioning
@@ -257,7 +350,7 @@ contains
     call setup_ncells_single_veg_patch(ncells=2, pft_type=1)
     call this%set_inputs(rain=rain, snow=snow, temperature=temp)
 
-    call partition_precip(bounds, this%atm2lnd_inst, this%sh_from_conversion)
+    call this%call_partition_precip()
 
     ! grid cell 1: converts snow to rain
     sens_heat_expected(1) = -1._r8 * snow(1) * mm_to_m * denh2o * hfus
diff --git a/src/main/test/atm2lnd_test/test_sens_heat_from_precip_conversion.pf b/src/main/test/atm2lnd_test/test_sens_heat_from_precip_conversion.pf
deleted file mode 100644
index 44ca36b9ec..0000000000
--- a/src/main/test/atm2lnd_test/test_sens_heat_from_precip_conversion.pf
+++ /dev/null
@@ -1,43 +0,0 @@
-module test_sens_heat_from_precip_conversion
-
-  ! Tests of atm2lndMod: sens_heat_from_precip_conversion
-  ! This module just tests edge cases that would be difficult to test from the
-  ! multi-point wrapper.
-
-  use pfunit_mod
-  use atm2lndMod
-  use shr_kind_mod, only : r8 => shr_kind_r8
-  use clm_varcon, only : hfus   ! latent heat of fusion for ice [J/kg]
-  use clm_varcon, only : denh2o ! density of liquid water [kg/m3]
-
-  implicit none
-
-  real(r8), parameter :: tol = 1.e-13_r8
-  real(r8), parameter :: mm_to_m = 1.e-3_r8  ! multiply by this to convert from mm to m
-
-contains
-
-  @Test
-  subroutine partialConversion_resultsInCorrectHeatFlux()
-    real(r8), parameter :: rain_old = 2._r8  ! [mm]
-    real(r8), parameter :: snow_old = 5._r8  ! [mm]
-    real(r8), parameter :: rain_new = 6._r8  ! [mm]
-    real(r8), parameter :: snow_new = 1._r8  ! [mm]
-    real(r8) :: sens_heat_flux  ! [W/m2 to atm]
-    real(r8) :: expected
-
-    call sens_heat_from_precip_conversion( &
-         rain_old = rain_old, &
-         snow_old = snow_old, &
-         rain_new = rain_new, &
-         snow_new = snow_new, &
-         sens_heat_flux = sens_heat_flux)
-
-    ! Snow to rain extracts energy, so results in a negative heat flux to atm
-    expected = -4._r8 * mm_to_m * denh2o * hfus
-    @assertEqual(expected, sens_heat_flux, tolerance=tol)
-
-  end subroutine partialConversion_resultsInCorrectHeatFlux
-
-end module test_sens_heat_from_precip_conversion
-
diff --git a/src/main/test/glcBehavior_test/test_glcBehavior.pf b/src/main/test/glcBehavior_test/test_glcBehavior.pf
index 90f12013a9..fe8f1fa31d 100644
--- a/src/main/test/glcBehavior_test/test_glcBehavior.pf
+++ b/src/main/test/glcBehavior_test/test_glcBehavior.pf
@@ -63,7 +63,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['multiple'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertFalse(glc_behavior%has_virtual_columns_grc(bounds%begg))
     @assertFalse(glc_behavior%get_collapse_to_atm_topo(bounds%begg))
@@ -82,7 +83,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['virtual'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertTrue(glc_behavior%has_virtual_columns_grc(bounds%begg))
     @assertFalse(glc_behavior%get_collapse_to_atm_topo(bounds%begg))
@@ -101,7 +103,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertFalse(glc_behavior%has_virtual_columns_grc(bounds%begg))
     @assertTrue(glc_behavior%get_collapse_to_atm_topo(bounds%begg))
@@ -120,7 +123,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertTrue(glc_behavior%melt_replaced_by_ice_grc(bounds%begg))
   end subroutine init_replaced_behaviorIsCorrect
@@ -137,7 +141,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['remains_in_place'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertFalse(glc_behavior%melt_replaced_by_ice_grc(bounds%begg))
   end subroutine init_remains_behaviorIsCorrect
@@ -154,7 +159,8 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertFalse(glc_behavior%ice_runoff_melted_grc(bounds%begg))
   end subroutine init_remainsIce_behaviorIsCorrect
@@ -171,11 +177,44 @@ contains
          glacier_region_map = [0], &
          glacier_region_behavior_str = ['single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['replaced_by_ice'], &
-         glacier_region_ice_runoff_behavior_str = ['melted'])
+         glacier_region_ice_runoff_behavior_str = ['melted'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
 
     @assertTrue(glc_behavior%ice_runoff_melted_grc(bounds%begg))
   end subroutine init_melted_behaviorIsCorrect
 
+  @Test
+  subroutine init_convertedToSnow_behaviorIsCorrect(this)
+    ! Make sure rain to snow conversion behavior is correct for 'converted_to_snow'
+    class(TestGlcBehavior), intent(inout) :: this
+    type(glc_behavior_type) :: glc_behavior
+
+    call glc_behavior%InitFromInputs(bounds%begg, bounds%endg, &
+         glacier_region_map = [0], &
+         glacier_region_behavior_str = ['single_at_atm_topo'], &
+         glacier_region_melt_behavior_str = ['replaced_by_ice'], &
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow'])
+
+    @assertFalse(glc_behavior%rain_to_snow_runs_off_grc(bounds%begg))
+  end subroutine init_convertedToSnow_behaviorIsCorrect
+
+  @Test
+  subroutine init_runsOff_behaviorIsCorrect(this)
+    ! Make sure rain to snow conversion behavior is correct for 'runs_off'
+    class(TestGlcBehavior), intent(inout) :: this
+    type(glc_behavior_type) :: glc_behavior
+
+    call glc_behavior%InitFromInputs(bounds%begg, bounds%endg, &
+         glacier_region_map = [0], &
+         glacier_region_behavior_str = ['single_at_atm_topo'], &
+         glacier_region_melt_behavior_str = ['replaced_by_ice'], &
+         glacier_region_ice_runoff_behavior_str = ['remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['runs_off'])
+
+    @assertTrue(glc_behavior%rain_to_snow_runs_off_grc(bounds%begg))
+  end subroutine init_runsOff_behaviorIsCorrect
+
   @Test
   subroutine init_multipleGridCells(this)
     class(TestGlcBehavior), intent(inout) :: this
@@ -187,7 +226,8 @@ contains
          glacier_region_map = [0, 1, 0], &
          glacier_region_behavior_str = ['multiple', 'virtual '], &
          glacier_region_melt_behavior_str = ['replaced_by_ice ', 'remains_in_place'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice', 'melted     '])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice', 'melted     '], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow', 'runs_off         '])
 
     @assertFalse(glc_behavior%has_virtual_columns_grc(bounds%begg))
     @assertTrue(glc_behavior%has_virtual_columns_grc(bounds%begg + 1))
@@ -200,6 +240,10 @@ contains
     @assertFalse(glc_behavior%ice_runoff_melted_grc(bounds%begg))
     @assertTrue(glc_behavior%ice_runoff_melted_grc(bounds%begg + 1))
     @assertFalse(glc_behavior%ice_runoff_melted_grc(bounds%begg + 2))
+
+    @assertFalse(glc_behavior%rain_to_snow_runs_off_grc(bounds%begg))
+    @assertTrue(glc_behavior%rain_to_snow_runs_off_grc(bounds%begg + 1))
+    @assertFalse(glc_behavior%rain_to_snow_runs_off_grc(bounds%begg + 2))
   end subroutine init_multipleGridCells
 
   ! ------------------------------------------------------------------------
@@ -287,7 +331,8 @@ contains
          glacier_region_map = [0, 1, 0], &
          glacier_region_behavior_str = ['multiple          ', 'single_at_atm_topo'], &
          glacier_region_melt_behavior_str = ['remains_in_place', 'remains_in_place'], &
-         glacier_region_ice_runoff_behavior_str = ['remains_ice', 'remains_ice'])
+         glacier_region_ice_runoff_behavior_str = ['remains_ice', 'remains_ice'], &
+         glacier_region_rain_to_snow_behavior_str = ['converted_to_snow', 'converted_to_snow'])
 
     ! Exercise