diff --git a/src/control/cam_snapshot_common.F90 b/src/control/cam_snapshot_common.F90
index 6a342b67be..8fd659113b 100644
--- a/src/control/cam_snapshot_common.F90
+++ b/src/control/cam_snapshot_common.F90
@@ -1235,7 +1235,14 @@ subroutine cam_pbuf_snapshot_all_outfld(lchnk, file_num, pbuf)
 
          ! Retrieve the pbuf data. Special handling for certain
          ! integer-type fields.
-         if( trim(pbuf_snapshot(i)%ddt_string) == 'clubbtop') then
+         ! This will allow data written out to not be mangled,
+         ! and also allow writing out snapshots with debug on in GNU compiler.
+         if( trim(pbuf_snapshot(i)%ddt_string) == 'clubbtop' .or. &
+             trim(pbuf_snapshot(i)%ddt_string) == 'ZM_JT' .or. &
+             trim(pbuf_snapshot(i)%ddt_string) == 'ZM_MAXG' .or. &
+             trim(pbuf_snapshot(i)%ddt_string) == 'ZM_IDEEP' .or. &
+             trim(pbuf_snapshot(i)%ddt_string) == 'NMXRGN' .or. &
+             trim(pbuf_snapshot(i)%ddt_string) == 'ACNUNM') then
             call pbuf_get_field(pbuf, pbuf_idx, tmpptr2d_int)
             ! copy into real
             allocate(tmpptr2d(size(tmpptr2d_int, 1), size(tmpptr2d_int, 2)))
diff --git a/src/physics/cam/physpkg.F90 b/src/physics/cam/physpkg.F90
index ad0837ea9b..2f0df4c81f 100644
--- a/src/physics/cam/physpkg.F90
+++ b/src/physics/cam/physpkg.F90
@@ -1531,6 +1531,12 @@ subroutine tphysac (ztodt,   cam_in,  &
     ifld = pbuf_get_index('AST')
     call pbuf_get_field(pbuf, ifld, ast, start=(/1,1,itim_old/), kount=(/pcols,pver,1/) )
 
+    ! zero out local variables that may be written to snapshot for safety.
+    fh2o(:) = 0._r8         ! used in chem_timestep_tend.
+    surfric(:) = 0._r8      ! out from vertical_diffusion_tend.
+    obklen(:) = 0._r8       ! out from vertical_diffusion_tend.
+    flx_heat(:) = 0._r8     ! first out from gw_drag_cam.
+
     !
     ! accumulate fluxes into net flux array for spectral dycores
     ! jrm Include latent heat of fusion for snow
@@ -2358,6 +2364,19 @@ subroutine tphysbc (ztodt, state,  &
 
     call t_stopf('bc_init')
 
+    ! Zero-initialize subroutine-level variables for snapshot
+    cmfmc(:,:) = 0._r8
+    cmfcme(:,:) = 0._r8
+    zdu(:,:) = 0._r8
+    rliq(:) = 0._r8
+    rice(:) = 0._r8
+    dlf(:,:) = 0._r8
+    dlf2(:,:) = 0._r8
+    rliq2(:) = 0._r8
+    det_s(:) = 0._r8
+    det_ice(:) = 0._r8
+    net_flx(:) = 0._r8
+
     !===================================================
     ! Global mean total energy fixer
     !===================================================
@@ -2515,10 +2534,6 @@ subroutine tphysbc (ztodt, state,  &
        dlf(:,:) = 0._r8
     end if
 
-    ! Zero-initialize subroutine-level variables for snapshot
-    dlf2(:,:) = 0._r8
-    rliq2(:) = 0._r8
-
     if (trim(cam_take_snapshot_before) == "convect_shallow_tend") then
        call cam_snapshot_all_outfld_tphysbc(cam_snapshot_before_num, state, tend, cam_in, cam_out, pbuf, &
            flx_heat, cmfmc, cmfcme, zdu, rliq, rice, dlf, dlf2, rliq2, det_s, det_ice, net_flx)
diff --git a/src/physics/cam7/physpkg.F90 b/src/physics/cam7/physpkg.F90
index a3f0c49fe6..c5dccb3647 100644
--- a/src/physics/cam7/physpkg.F90
+++ b/src/physics/cam7/physpkg.F90
@@ -1623,6 +1623,15 @@ subroutine tphysac (ztodt,   cam_in,  &
     call pbuf_get_field(pbuf, rliqbc_idx, rliqbc)
     rliq(:ncol) = rliqbc(:ncol)
 
+    ! zero out local variables that may be written to snapshot for safety.
+    fh2o(:) = 0._r8         ! used in chem_timestep_tend.
+    surfric(:) = 0._r8      ! out from vertical_diffusion_tend.
+    obklen(:) = 0._r8       ! out from vertical_diffusion_tend.
+    flx_heat(:) = 0._r8     ! first out from gw_drag_cam.
+    det_s(:) = 0._r8        ! out from clubb_tend_cam.
+    det_ice(:) = 0._r8      ! out from clubb_tend_cam.
+    net_flx(:) = 0._r8      ! out from radiation_tend.
+
     !
     ! accumulate fluxes into net flux array for spectral dycores
     ! jrm Include latent heat of fusion for snow
@@ -2788,6 +2797,17 @@ subroutine tphysbc (ztodt, state,  &
 
     call t_stopf('bc_init')
 
+    ! Zero-initialize subroutine-level variables for snapshot
+    cmfmc(:,:) = 0._r8
+    cmfcme(:,:) = 0._r8
+    zdu(:,:) = 0._r8
+    rliq(:) = 0._r8
+    rice(:) = 0._r8
+    dlf(:,:) = 0._r8
+    dlf2(:,:) = 0._r8
+    rliq2(:) = 0._r8
+    net_flx(:) = 0._r8
+
     !===================================================
     ! Global mean total energy fixer
     !===================================================