The National Weather Service office in Great Falls issued a Special Weather Statement early Tuesday morning warning of patchy fog across portions of North Central Montana. The statement, issued at 3:38 a.m. MDT on September 16, flagged visibility reductions to less than half a mile at times.
The affected area includes Cascade, Belt, and Choteau, with the Interstate 15 corridor from Ulm north to Sieben Flats specifically called out. For Helena commuters heading north on I-15 in the early morning hours, that stretch of highway — where the road opens up through the canyon and into the flats — can be particularly unforgiving in low-visibility conditions.
The NWS reminded drivers to reduce speed in areas of poor visibility. The statement was in effect for morning hours; conditions were expected to improve as temperatures rose through the day.