diff --git a/src/icesat2_tracks/analysis_db/A02c_IOWAGA_thredds_prior.py b/src/icesat2_tracks/analysis_db/A02c_IOWAGA_thredds_prior.py
index b6f5f3d..6ef90f0 100644
--- a/src/icesat2_tracks/analysis_db/A02c_IOWAGA_thredds_prior.py
+++ b/src/icesat2_tracks/analysis_db/A02c_IOWAGA_thredds_prior.py
@@ -448,7 +448,7 @@ def test_nan_frac(imask):
             return ((~imask).sum() / imask.size).data < 0.3
 
         while test_nan_frac(ice_mask_prior):
-            _logger.debug("%s", lat_range_prior)
+            _logger.debug("lat range prior: %s", lat_range_prior)
             lat_range_prior = lat_range_prior[0] + 0.5, lat_range_prior[1] + 0.5
             G_prior = sel_data(G_beam, lon_range, lat_range_prior)
             ice_mask_prior = ice_mask.sel(latitude=G_prior.latitude)