A bitter blast of arctic air from Canada is expected to bring “life-threatening” cold to parts of the United States in the run-up to Christmas, according to weather forecasters.
A strong arctic high-pressure system extending from western Canada to the northern Plains is expected to bring “very cold air” across the region this week, extending into parts of the Pacific Northwest, according to the National Weather Service. From the Northwest to the Appalachians, 48 million people were under winter alerts as of Tuesday afternoon. Wind chill and freeze warnings were issued for 42 million people across more than 20 states.
Along with the bitter cold, snow is expected to hit parts of the United States, causing “pre-holiday travel headaches,” according to the forecast.
As the cold air mass penetrates deeper into Washington, “an approaching storm system and surge of moisture will lead to widespread snow to impact northern and western portions of The Evergreen State,” according to the weather service. More than a foot of snow has already fallen in parts of Washington, and it will continue to fall in the Cascades and northern Rockies through Tuesday evening.
The highest snowfall amounts are expected in the Cascades and into northern Idaho, northwest Montana, and western Wyoming, according to the weather service, adding, “These regions will have the best chances for over a foot of snow.”
The dangerous arctic air over the northern Plains and western Canada is expected to move south, following a system that crossed the Pacific Northwest on Tuesday.
Cold weather, combined with wind gusts of up to 60 mph, could bring “life-threatening” wind chill values as low as minus-40 degrees to parts of the central and north-central United States, according to the weather service.
“This level of cold can be life threatening and cause frostbite on exposed skin in as little as 10 minutes,” it said.
Wind chill warnings and watches have been issued in 17 states ranging from Washington to Texas.
Snow is also expected to exacerbate “pre-holiday travel headaches” from the central Plains to the Midwest and the Great Lakes as a major storm approaches, according to the weather service.
“Areas of light to moderate snow are likely along and behind the cold front as it impacts the central Plains and Upper Mississippi Valley on Wednesday and Thursday,” it said.