The system will hit in the Kalispell, West Glacier and Eureka area first, and shift to the south Tuesday and Wednesday. Then, the Missions, Missoula, the Bitterroot and Lost Trail areas will be in the center of the winter blast.

A weather band some 50 miles wide, possibly from Lookout Pass to around Drummond, will set up, and valleys underneath can expect to be hit hardest. The National Weather Service anticipates 6 inches to 10 inches in the valleys, and 10 to 15 inches in mountain passes.

Thursday morning brings the potential for freezing rain, and the weather will hamper travel. Areas from Missoula to the south have the highest potential for rain and freezing rain, but the band could shift.

"Travel conditions could get very nasty for Thursday morning," Pallister said.

Temperatures are forecast to be in the single digits in the northwest part of the state and in the 10s and 20s in the southwest part. Winds will blow as high as 20 mph to 30 mph.

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So far, it isn't clear when the pelting will dissipate, and all that makes for some extremely dangerous conditions for backcountry travelers, said Steve Karkanen, director of the West Central Montana Avalanche Center.