The National Weather Service office in Great Falls issued a Winter Weather Advisory Thursday for several mountain areas in and around Lewis and Clark County, with snow and gusty winds forecast through midnight Friday.
The advisory covers the Big Belt, Bridger, and Castle Mountains, as well as the Upper Blackfoot drainage, MacDonald Pass, and the Ruby and Southern Beaverhead Mountains. Total snow accumulations of two to five inches were expected, with winds gusting up to 35 mph.
MacDonald Pass on U.S. Highway 12 west of Helena is the stretch most likely to affect Helena commuters and travelers heading toward Missoula. NWS specifically flagged the Friday evening commute as the period of highest impact, when accumulating snow and reduced visibility could catch drivers off guard.
Montana Highway Patrol and MDT recommend carrying winter emergency supplies in the vehicle when crossing mountain passes this time of year. Conditions on MacDonald Pass can change quickly, and the pass has seen serious accidents in early-season snow events in past years.