diff --git a/components/mpas-ocean/src/shared/mpas_ocn_time_average_coupled.F b/components/mpas-ocean/src/shared/mpas_ocn_time_average_coupled.F
index db3d100b4e2f..4b50ef499d8b 100644
--- a/components/mpas-ocean/src/shared/mpas_ocn_time_average_coupled.F
+++ b/components/mpas-ocean/src/shared/mpas_ocn_time_average_coupled.F
@@ -426,10 +426,10 @@ subroutine ocn_time_average_coupled_accumulate(statePool, forcingPool, timeLevel
 
         ! find vertical level that is just above the critical depth reference level
         ! this does not account for depression due to ice shelf cavities or sea ice
-        iLevelCritDepth = 1
+        iLevelCritDepth = nVertLevels  ! default to deepest layer if we don't find the desired depth
         do iLevel = 1, nVertLevels
            if(refBottomDepth(iLevel) > config_2d_thermal_forcing_depth) then
-              iLevelCritDepth = iLevel-1
+              iLevelCritDepth = iLevel
               exit
            end if
         end do