A High Wind Warning covering MacDonald Pass, the Southern Rocky Mountain Front, Upper Blackfoot, and a broad swath of north-central Montana went into effect June 16, running from noon through midnight, according to the National Weather Service office in Great Falls. The warning was among the more geographically expansive single-day wind events issued for the region this season.
Forecasters called for sustained westerly winds of 30 to 40 mph with gusts up to 65 mph across the warned zones, which also included the East Glacier Park Region, Northern and Southern High Plains, and portions of Glacier, Toole, and Pondera counties. For Helena commuters, MacDonald Pass on U.S. Highway 12 west of town is the most directly relevant corridor — it is one of the first areas to see dangerous wind conditions when strong westerly flow develops across the Continental Divide.
The NWS flagged concerns for outdoor recreation, boating, and high-profile vehicle travel. Gusts in the 60-plus mph range on MacDonald Pass can push large trucks and vehicles towing trailers across lane lines, and the pass has a history of wind-related incidents during strong frontal passages. Motorists were advised to check 511mt.com for road conditions before crossing.