Winter Storm and High Wind in Montana, December 18 to 19, 2025

Heavy snow and strong winds brought blizzard conditions to the backcountry, severely impacting mountain passes on December 18 and 19. SNOTEL sensors recorded massive gains, including a 17-inch snow depth increase at Lolo Pass and 12 inches at Saddle Mountain. |Travel conditions deteriorated rapidly on the afternoon of December 18 as intense snowfall rates including 1 inch per hour near West Fork led to rapid accumulation on roadways despite ongoing mitigation efforts. Wind gusts of 25 to 35 mph at Lost Trail Pass created localized blizzard-like conditions with near-zero visibility. The treacherous weather caused severe transportation disruptions on US-12, triggering a chain requirement between mile markers 0 and 4 by 1913MST. The following morning, an incident completely blocked both lanes at milepost 2.0, leading to an official declaration of Severe Driving Conditions that lasted through midday on December 19.

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.

The Flathead Electric Co-op reported that several poles on Blacktail Mountain were snapped from the strong winds.

The Hungry Horse RAWS recorded a peak wind gust of 66 mph between 0311MST and 0411MST, followed by subsequent gusts of 55 mph and 57 mph through 0611MST.

The high winds caused immediate and severe utility disruptions. Flathead Electric Cooperative reported that the main lines feeding West Glacier and the Canyon were down. By 0730MST, approximately 8,600 members across their service territory had lost power. While crews made significant progress throughout the day, the Flathead County Sheriff's Office reported that approximately 3,000 electric meters remained without power by 1600MST.

Additional property and infrastructure damage was reported within Glacier National Park and the surrounding corridors. Park dispatch reported two 12-inch diameter trees fell at the foot of Lake McDonald, and another tree blocked a local bike path. In the Apgar area, a large fir tree crashed onto a cabin, requiring a crane for removal. Travel was also impacted, with the Montana Department of Transportation reporting 8 to 9 downed trees blocking the route between Essex and Goat Lick.