Drivers heading out early Tuesday had reason to slow down. The National Weather Service office in Great Falls issued a Special Weather Statement at 3:38 a.m. MDT on September 16 warning of patchy fog across portions of North Central Montana, with visibility dropping below half a mile at times.
The affected area includes Cascade, Belt, and Choteau, along with the Interstate 15 corridor stretching from Ulm to Sieben Flats — a stretch of highway that Helena-area commuters and freight traffic use daily. The NWS statement did not include a specific end time for the fog, but morning fog events in the region typically burn off as temperatures rise.
The agency reminded drivers to reduce speeds in areas of reduced visibility. Fog-related crashes on I-15 have been a recurring concern in Lewis and Clark and Cascade counties during late summer and early fall mornings, when overnight temperatures begin to dip and ground moisture lingers. If you were on the highway before sunrise Tuesday, you already knew what the forecast was talking about.