diff --git a/parm/postcntrl_gefs.xml b/parm/postcntrl_gefs.xml
index e6f2f502e..9b1349653 100644
--- a/parm/postcntrl_gefs.xml
+++ b/parm/postcntrl_gefs.xml
@@ -1013,6 +1013,12 @@
        <scale>6.0</scale>
     </param>
 
+    <param>
+        <shortname>ICEG_ON_SPEC_ALT_ABOVE_MEAN_SEA_LVL</shortname>
+        <level>10.</level>
+        <scale>4.0</scale>
+    </param>
+
     <!--  comments wherever I like -->
   </paramset>
 </postxml>
diff --git a/parm/postcntrl_gefs_f00.xml b/parm/postcntrl_gefs_f00.xml
index 94a0fb4f5..f69da6be1 100644
--- a/parm/postcntrl_gefs_f00.xml
+++ b/parm/postcntrl_gefs_f00.xml
@@ -774,6 +774,11 @@
        <scale>6.0</scale>
     </param>
 
+    <param>
+       <shortname>ICEG_ON_SPEC_ALT_ABOVE_MEAN_SEA_LVL</shortname>
+       <level>10.</level>
+       <scale>4.0</scale>
+    </param>
 
     <!--  comments wherever I like -->
   </paramset>
diff --git a/parm/postxconfig-NT-GEFS-F00.txt b/parm/postxconfig-NT-GEFS-F00.txt
index f2dc25ad1..7afbf8152 100644
--- a/parm/postxconfig-NT-GEFS-F00.txt
+++ b/parm/postxconfig-NT-GEFS-F00.txt
@@ -1,5 +1,5 @@
 1
-130
+131
 GFSPRS
 0
 ncep_nco
@@ -4827,3 +4827,40 @@ hybrid_lvl
 ?
 ?
 ?
+588
+ICEG_ON_SPEC_ALT_ABOVE_MEAN_SEA_LVL
+?
+1
+tmpl4_0
+ICEG
+?
+?
+spec_alt_above_mean_sea_lvl
+0
+?
+1
+10.
+?
+0
+?
+0
+?
+?
+?
+0
+0.0
+0
+0.0
+?
+0
+0.0
+0
+0.0
+1
+4.0
+0
+0
+0
+?
+?
+?
diff --git a/parm/postxconfig-NT-GEFS.txt b/parm/postxconfig-NT-GEFS.txt
index 8de79446f..cd614c9f5 100644
--- a/parm/postxconfig-NT-GEFS.txt
+++ b/parm/postxconfig-NT-GEFS.txt
@@ -1,5 +1,5 @@
 1
-174
+175
 GFSPRS
 0
 ncep_nco
@@ -6455,3 +6455,40 @@ hybrid_lvl
 ?
 ?
 ?
+588
+ICEG_ON_SPEC_ALT_ABOVE_MEAN_SEA_LVL
+?
+1
+tmpl4_0
+ICEG
+?
+?
+spec_alt_above_mean_sea_lvl
+0
+?
+1
+10.
+?
+0
+?
+0
+?
+?
+?
+0
+0.0
+0
+0.0
+?
+0
+0.0
+0
+0.0
+1
+4.0
+0
+0
+0
+?
+?
+?
diff --git a/sorc/ncep_post.fd/CALVESSEL.f b/sorc/ncep_post.fd/CALVESSEL.f
index cf5d11b4d..5d314fb39 100644
--- a/sorc/ncep_post.fd/CALVESSEL.f
+++ b/sorc/ncep_post.fd/CALVESSEL.f
@@ -1,8 +1,9 @@
       SUBROUTINE CALVESSEL(ICEG)
 ! Algorithm for calculating ice growth rate
-      use vrbls2d, only: sst, u10h, v10h, tshltr
+      use vrbls2d, only: sst, u10h, v10h, tshltr, pshltr
       use masks, only: sm, sice
       use ctlblk_mod, only: jsta, jend, im, spval
+      use params_mod, only: capa
 !-------------------------------------------
       implicit none
       integer I, J
@@ -28,11 +29,13 @@ SUBROUTINE CALVESSEL(ICEG)
             ICEG(i,j)=0.
             CYCLE
           endif
+! Covert to shelter level T
+          TSHLTR_C=TSHLTR(I,J)*(PSHLTR(I,J)*1.E-5)**CAPA
 
 !!! CHANGE TEMP to FROM K to C
 !!! TEMPERATURE CHECK
           SST_C=SST(I,J)-C2K  
-          TSHLTR_C=TSHLTR(I,J)-C2K
+          TSHLTR_C=TSHLTR_C-C2K
           if((SST_C.lt.-1.7).OR. &
              (SST_C.gt.12.0)) then
             ICEG(I,j)=0.