Seventeen states across the United States have been issued cold weather warnings and advisories as winter finally takes hold in the country.

Parts of Alaska, Washington, Oregon, California, Utah, Wyoming, Colorado and a tiny portion of South Dakota have been considering winter weather advisories by the National Weather Service. Sections of Arizona, New Mexico, Washington, Texas, Oklahoma, Utah, Colorado, Kansas and Nebraska received frost warnings.

A handful of counties in Wisconsin and Minnesota have received a winter storm watch, and parts of Oregon, Wyoming and South Dakota are under winter storm warnings.

“Moderate to heavy snowfall across parts of the South Cascades and Northern Intermountain region,” the NWS said in a forecast discussion.

The majority of warnings and advisories are in effect until this morning, while some of them will last until Friday.

Large amounts of snow are expected in Winter Weather Advisory and Winter Storm Warning areas, particularly at higher elevations.

Up to 2 feet of snowfall is forecast for Oregon’s Cascades, with 15 to 18 inches expected in Wyoming’s Bighorn and Wind River Mountains; 12 inches in Colorado’s many mountains; and up to 20 inches in the Washington Cascades.

“Heavy snowfall is expected above 5,000 feet. Total snow accumulations of 1 to 2 feet,” the NWS office in Medford, Oregon, said.

Additionally, temperatures are expected to drop well below freezing in affected areas. by frost warnings. Temperatures can reach 21 degrees Fahrenheit in parts of New Mexico and 22 to 23 degrees Fahrenheit in parts of Colorado.

A winter weather advisory is issued if “some amount of freezing rain is expected, or when 2 to 4 inches of snow (alone or in combination with sleet and freezing rain) is expected to cause significant inconvenience, but not serious enough to warrant a warning,” the NWS added.

A Freeze Warning is issued when “significant and widespread freezing temperatures are expected,” and a Winter Storm Warning is issued “when a significant combination of hazardous winter conditions occurs or is imminent.”

The NWS defines significant and hazardous winter conditions as a combination of “5 inches or more of snow/sleet in a 12-hour period or 7 inches or more of snow/sleet in a 24-hour period,” plus accumulation ice that can damage trees or power lines, and “a potentially fatal or damaging combination of snow and/or ice accumulation and wind.”

In areas subject to Winter Weather Advisories and Winter Storm Warnings, the NWS said road conditions can be extremely slippery and dangerous.

“People should consider delaying any travel. If travel is absolutely necessary, drive with extreme caution. Consider carrying a winter storm kit, including items such as tire chains, jumper cables, flashlight, shovel, blankets and extra clothing,” the NWS Billings, Montana, office said.

“Also take water, a first aid kit, and anything else that might help you survive in case you get stuck.”

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