Squalls from across the Great Lakes brought up to a foot of snow Monday to the upper Midwest and sent temperatures diving.
Snowstorms, some accompanied by strong winds, prompted snow advisories and winter storm warnings from the Great Lakes region to Texas.
A foot of snow had fallen in northwestern Indiana, and as much as 20 inches was expected before the storm ended.
State police issued a travel advisory for the area around the southern tip of Lake Michigan.
Eight inches of snow fell in northwest Pennsylvania and seven inches fell in northern Ohio. Up to a foot of snow was expected at resorts in West Virginia.
Snow also fell overnight in Detroit, Louisville, Ky.; Pittsburgh, Pa.; Buffalo, N.Y., and Boston. Slightly farther south, New York and Philadelphia had rain.
Meanwhile, gale warnings were issued along the coast of Virginia and North Carolina, and lake wind advisories were in effect for northern Alabama and all of South Carolina.
Strong northwesterly winds ushered cold arctic air into the eastern and south-central parts of the country.
Temperatures on Monday were below freezing from the Rocky Mountains to the Appalachians. Temperatures were in the single digits and below zero across the upper Mississippi Valley and in upper Michigan.
The morning low Monday in the lower 48 states was 25 degrees below zero in International Falls, Minn.
Weather officials said temperatures would continue to drop. The temperature was expected to dip to 15 to 25 degrees below zero overnight in the eastern Upper Peninsula of Michigan.