Special Weather Statement issued May 25 at 7:40AM MDT by NWS Great Falls MT

Patchy fog, which was locally dense in some areas, will reduce
visibilities across Hill and Blaine Counties, most notably in the
Milk River Valley through approximately 9 AM MDT. Travelers
should be prepared for visibilities as low as one quarter of a
mile in the densest fog. Slow down, use low beam headlights, and
allow extra spacing between vehicles if traveling this morning.