Heavy snow and gusty winds generated by a potent storm system heading across the West will persist through late Monday. Some people from Oregon to the western Dakotas will face treacherous travel conditions and perhaps even power outages.
Portions of southern Montana, northern Wyoming and eastern Idaho will bear the brunt of the storm tonight into late Monday as the storm heads eastward from northern Utah and eventually emerges over the central High Plains.
Snow will become heavier over the mountain ranges of these areas tonight, while rain mixes with and changes over to snow across many of the valley locations.
Between 6 and 12 inches is expected to fall by Monday evening, affecting areas such as Yellowstone National Park, the section of Interstate 90 from Livingston, Mont., to near Sheridan, Wyo., and the section of I-94 from Billings, Mont., to near Miles City, Mont.
Amounts over a foot will be reached at elevations over 5,000 or 6,000 feet across this general region. A few of the east- and northeast-facing slopes could even pick up several feet of snow through Monday as strong east-northeasterly winds set up, leading to enhanced upslope snowfall.
The combination of snow accumulating on roadways and winds gusting as high as 40 or 50 mph, causing visibility-reducing blowing snow, will make for treacherous travel conditions in some areas.
In addition, the snow will be wet and heavy like many early season snowfalls. The weight of the snow could down tree branches and power lines in a few areas, creating power outages for hundreds of customers
Lesser accumulations are expected from eastern Oregon through central and northern Wyoming and eventually even the western Dakotas by late Monday. Still, several inches of snow will be enough to make roads slippery for a time in places like Pocatello, Idaho and Casper, Wyo.
As the storm heads farther east across the Plains Monday night, snow will taper off west-to-east with a dry day following Tuesday. Toward the middle and end of the week, a cold front plunging southward from Canada could return snow to parts of the northern Rockies and northern High Plains.