diff --git a/modules/util/util.py b/modules/util/util.py
index 4ce4560e89795cc5344188fb661319db1dab3da0..50470704890ae959a080b28c9b1b831e8afbd0fa 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -569,13 +569,13 @@ def write_icing_file(clvrx_str_time, preds_dct, probs_dct, x, y, lons, lats):
     flt_lvls = list(preds_dct.keys())
     for flvl in flt_lvls:
         preds = preds_dct[flvl]
-        icing_pred_ds = h5f_out.create_dataset('icing_prediction_level_'+flvl, data=preds, dtype='i2')
+        icing_pred_ds = h5f_out.create_dataset('icing_prediction_level_'+str(flvl), data=preds, dtype='i2')
         icing_pred_ds.attrs.create('coordinates', data='y x')
         icing_pred_ds.attrs.create('grid_mapping', data='Projection')
 
     for flvl in flt_lvls:
         probs = probs_dct[flvl]
-        icing_pred_ds = h5f_out.create_dataset('icing_probability_level_'+flvl, data=probs, dtype='f4')
+        icing_pred_ds = h5f_out.create_dataset('icing_probability_level_'+str(flvl), data=probs, dtype='f4')
         icing_pred_ds.attrs.create('coordinates', data='y x')
         icing_pred_ds.attrs.create('grid_mapping', data='Projection')