Winter Weather — Lower Clark Fork Region, Montana

2025-12-18 to 2025-12-19 · Lower Clark Fork Region, Montana

Event narrative

As conditions rapidly deteriorated on the afternoon of December 18, highway officials issued a chains required restriction at 1530MST. Just fifteen minutes later, at 1545MST, a semi-truck spun out in the hazardous conditions, completely blocking the westbound lanes of the highway. The Lookout Pass SNOTEL reported a 5-inch snow depth increase.

Wider weather episode

Just two days after a historic windstorm devastated the region, another strong atmospheric river-connected wind event impacted the area during the early morning hours of December 19, severely compounding ongoing recovery efforts. Heavy snow combined with strong winds brought blizzard conditions in the backcountry.

Source: NOAA Storm Events Database, event_id 1307753. Narrative written by the NWS forecast office that issued the report.