The record cold wave pressed southward and eastward yesterday, threatening crops in southern Texas and California and covering highways with deadly sheets of ice across the Plains and Midwest.
Temperatures fell to more than 40 degrees below zero in places, the National Weather Service said.
Utilities fought to restore electricity and gas service to thousands of shivering customers.
In sharp contrast to the cold and snow, the East still had mild weather. Boston hit a record 62 during the morning, and in the Washington area the high was a steamy 64 but short of the record 72 set in 1889. Heavy rain and flooding forced the evacuations of more than 90 people across Tennessee, state emergency officials said.
Tornadoes swirled around Mississippi for the third straight day as crews tried to assess damage and start cleaning up from Friday's twisters, which killed two people and injured many more.
At least 24 deaths have been blamed on the weather since Tuesday, the majority in traffic accidents on slippery roads.
Denver hit a record low yesterday of 25 below zero, and in northern Nevada, Winnemucca dropped to 37 below, the coldest temperature registered there in 100 years. Los Angeles hit a record 33, and Stanley, Idaho, registered a low of 46 below zero.
In southern Arizona, the desert city of Tucson had snow flurries.
The Arctic air hit the Chicago area during the night, sending temperatures tumbling from the mild 40s Friday evening to the teens yesterday morning, and highways throughout the state were icy.
An Amtrak passenger train carrying 300 people was stuck in Devils Lake, N.D., for three hours when the fuel in the engines froze, a Burlington-Northern Railroad spokesman said. Welders were called in to help thaw out the engines. The temperature was 20 below and the wind chill factor was 50 below.
Utilities in northwest Washington and the Puget Sound area reported repairs were still being made to power lines damaged during Tuesday's snow and windstorm.
Utility crews worked to restore natural gas service to thousands of homes in frigid southern Oregon.
The cold also contributed to utility breakdowns in the San Francisco area and in the Texas Panhandle.
Bitter cold was reported in southern Texas, with up to a half-inch of ice on Kerrville streets. In the Rio Grande Valley, citrus growers still reeling from a late winter freeze a year ago were braced for another damaging frost.
In California, the heavily farmed San Joaquin Valley had record lows ranging from 19 at Fresno to the teens in the Bakersfield area, the weather service said.