diff --git a/modules/util/util.py b/modules/util/util.py
index 11c74becad8654ac1b531725724b82ea9bcdac0c..788400ab765dd417734f724484225192aef8f8bb 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -859,7 +859,9 @@ def write_icing_file_nc4(clvrx_str_time, output_dir, preds_dct, probs_dct,
         icing_prob_ds.setncattr('missing', np.nan)
     icing_prob_ds[:,] = max_prob
 
-    max_lvl = np.argmax(prob_s, axis=2)
+    prob_s = np.where(prob_s < prob_thresh, -1.0, prob_s)
+    max_lvl = np.where(np.all(prob_s == -1, axis=2), -1, np.argmax(prob_s, axis=2))
+    # max_lvl = np.argmax(prob_s, axis=2)
     if has_time:
         max_lvl = max_lvl.reshape((1, y.shape[0], x.shape[0]))