diff --git a/dev/parm/config/gfs/config.snowanl.j2 b/dev/parm/config/gfs/config.snowanl.j2
index b88cb42976..6745a5f7e7 100644
--- a/dev/parm/config/gfs/config.snowanl.j2
+++ b/dev/parm/config/gfs/config.snowanl.j2
@@ -14,6 +14,7 @@ export APPLY_INCR_NML_TMPL="${PARMgfs}/gdas/snow/apply_incr_nml.j2"
 
 export TASK_CONFIG_YAML="${PARMgfs}/gdas/snow/snow_det_config.yaml.j2"
 export OBS_LIST_YAML="${PARMgfs}/gdas/snow/snow_obs_list.yaml.j2"
+export ims_scf_obs_suffix="asc" # asc-ascii; nc-netcdf
 
 export PREP_SNOCVR_SNOMAD_YAML="${PARMgfs}/gdas/snow/prep/prep_snocvr_snomad.yaml.j2"
 export OBSBUILDER="${USHgfs}/bufr_snocvr_snomad.py"
diff --git a/sorc/gdas.cd b/sorc/gdas.cd
index dd911ba37f..e563476ec2 160000
--- a/sorc/gdas.cd
+++ b/sorc/gdas.cd
@@ -1 +1 @@
-Subproject commit dd911ba37f5c98a03e5e7cf89699d280e79f538b
+Subproject commit e563476ec250e20881b5b7cf7bb4ed020887f2ae
diff --git a/ush/python/pygfs/task/snow_analysis.py b/ush/python/pygfs/task/snow_analysis.py
index 5109070f2b..f9b1ef5a3e 100644
--- a/ush/python/pygfs/task/snow_analysis.py
+++ b/ush/python/pygfs/task/snow_analysis.py
@@ -50,12 +50,11 @@ def __init__(self, config: Dict[str, Any]):
         _res = int(self.task_config['CASE'][1:])
 
         # if 00z, do SCF preprocessing
-        _ims_file = os.path.join(self.task_config.COMIN_OBS, f'{self.task_config.OPREFIX}imssnow96.asc')
-        logger.info(f"Checking for IMS file: {_ims_file}")
-        if self.task_config.cyc == 0 and os.path.exists(_ims_file):
-            _DO_IMS_SCF = True
-        else:
-            _DO_IMS_SCF = False
+        _ims_file = os.path.join(
+            self.task_config.COMIN_OBS,
+            f'{self.task_config.OPREFIX}imssnow96.{self.task_config.ims_scf_obs_suffix}'
+        )
+        _DO_IMS_SCF = (self.task_config.cyc == 0 and os.path.exists(_ims_file))
 
         # Extend task_config with variables repeatedly used across this class
         self.task_config.update(AttrDict(
diff --git a/ush/python/pygfs/task/snowens_analysis.py b/ush/python/pygfs/task/snowens_analysis.py
index c876d94f29..984d38dcad 100644
--- a/ush/python/pygfs/task/snowens_analysis.py
+++ b/ush/python/pygfs/task/snowens_analysis.py
@@ -53,12 +53,11 @@ def __init__(self, config: Dict[str, Any]):
         _res = int(self.task_config['CASE_ENS'][1:])
 
         # if 00z, do SCF preprocessing
-        _ims_file = os.path.join(self.task_config.COMIN_OBS, f'{self.task_config.OPREFIX}imssnow96.asc')
-        logger.info(f"Checking for IMS file: {_ims_file}")
-        if self.task_config.cyc == 0 and os.path.exists(_ims_file):
-            _DO_IMS_SCF = True
-        else:
-            _DO_IMS_SCF = False
+        _ims_file = os.path.join(
+            self.task_config.COMIN_OBS,
+            f'{self.task_config.OPREFIX}imssnow96.{self.task_config.ims_scf_obs_suffix}'
+        )
+        _DO_IMS_SCF = (self.task_config.cyc == 0 and os.path.exists(_ims_file))
 
         # Extend task_config with variables repeatedly used across this class
         self.task_config.update(AttrDict(