diff --git a/airflow/www/views.py b/airflow/www/views.py
index 8be5bb1ed101b..bd4efb211caf8 100644
--- a/airflow/www/views.py
+++ b/airflow/www/views.py
@@ -2287,7 +2287,11 @@ def _clear_dag_tis(
         except AirflowException as ex:
             return redirect_or_json(origin, msg=str(ex), status="error", status_code=500)
 
-        assert isinstance(tis, collections.abc.Iterable)
+        if not isinstance(tis, collections.abc.Iterable):
+            raise AssertionError(
+                f"Expected dag.clear() to return an iterable for dry runs, got {tis} instead."
+            )
+
         details = [str(t) for t in tis]
 
         if not details: