Sonali Tiwary
Montana I-90 Winter Storm Warning: Snow and Strong Gusts on Mountain Passes
Heading over Montana's mountain passes this weekend? Expect snow and strong gusts on Interstate 90, with a Winter Storm Warning now in effect for Homestake and MacDonald passes. Check conditions before you leave.
The National Weather Service in Missoula upgraded Homestake Pass and MacDonald Pass to a Winter Storm Warning, effective from 6 p.m. MDT October 10 to 6 a.m. MDT October 12. The warning forecasts 3 to 9 inches of snow and gusts up to 45 mph. Lookout Pass is not listed in that Missoula product and should be checked separately with its responsible forecast office.
Drivers face slush and black ice, especially truckers without chains. Residents and farmers should check local conditions, since freeze impacts depend on crop, growth stage, exposure and local temperatures. Check Montana Department of Transportation 511 road reports before you leave.
Which Montana passes are affected?
Homestake Pass on I-90 and MacDonald Pass on US-12 are under a Winter Storm Warning for 3 to 9 inches of snow and gusts up to 45 mph, per the NWS Missoula product.
Why early-season storms are tricky
Pavement is still warm in early October, so snow melts into a water layer. When temperatures fall after dark, that water can freeze into black ice, which is a thin, clear glaze that is hard to see. That is general guidance, not a claim about this specific storm's cause.
What to watch
Road updates are due as the warning period progresses. Check back for updates.
