diff --git a/lib/microwaveprop_web/live/contact_live/show.ex b/lib/microwaveprop_web/live/contact_live/show.ex
index 25ff5468..4b30a26a 100644
--- a/lib/microwaveprop_web/live/contact_live/show.ex
+++ b/lib/microwaveprop_web/live/contact_live/show.ex
@@ -1034,7 +1034,7 @@ defmodule MicrowavepropWeb.ContactLive.Show do
   defp propagation_mechanism(terrain, elevation_profile, hrrr, soundings, dist_km) do
     blocked? = terrain && terrain.verdict == "BLOCKED"
     ducting? = has_ducting?(hrrr, soundings)
-    enhanced_refraction? = hrrr && is_number(hrrr.min_refractivity_gradient) and hrrr.min_refractivity_gradient < -100
+    enhanced_refraction? = hrrr != nil && is_number(hrrr.min_refractivity_gradient) && hrrr.min_refractivity_gradient < -100
     long_path? = dist_km && dist_km > 100
 
     ducts = elevation_profile && elevation_profile.ducts || []