Fears of the unusual snowstorm led rangers at Glacier National Park to close some roads, and the storm may cause power failures for thousands of Montanans. Wet snow weighs down the leaves that remain on trees, and powerful winds on Saturday and Sunday, with the strong gusts, could bring down trees and power lines. A strong storm in early October 2017 left about 10,000 without power — and this year’s blizzard is expected to be worse.

The National Weather Service has issued a winter storm warning for more than a dozen counties in the northwest part of the state and a winter storm watch for at least 15 more. The storm is expected to calm down by Monday night.

Cut Bank, a small city just 25 miles south of Alberta, Canada, has never received more than 15.5 inches over a three-day period in September. It is forecast to get up to 30 inches from this weekend’s storm. Great Falls, the state’s third-largest city, is predicted to get up to a foot of snow, nearing the city’s record for a three-day storm, 13.2 inches, which was set in 1934.