Record cold persisted across the Rockies, Great Plains and Midwest Tuesday, canceling schooldays and putting strain on power grids nationwide.
Power was out for more than 80,000 in the U.S., many of them in Oregon, where more freezing rain is expected to complicate restoration efforts.
The Tennessee Valley Authority, which delivers power across seven states, asked customers to make cutbacks in power use. Grid managers in Texas also asked customers to conserve power.
There were more than 2,400 U.S. flights canceled Tuesday and more than 8,800 delays, according to the tracking website FlightAware.
School closures hit major cities from Oregon to the East Coast, where Washington, D.C. saw two inches of snow accumulate.
More than nine inches of snow have fallen in parts of Tennessee, close to twice as much as the annual average. Authorities in the state confirmed there had been six weather-related fatalities.
Other storm-related deaths included at least four in Portland, Oregon, according to The Associated Press. The deaths of three homeless people in Milwaukee are being investigated, with the suspected cause being hypothermia.
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The frigid temperatures have been affecting the country for days, causing even the NFL wild-card playoff game between the Buffalo Bills and Pittsburgh Steelers to be postponed from Sunday to Monday as snow blanketed Highmark Stadium in Orchard Park, New York.
Forecasters say another foot of snow could fall in the area this week.
The weather also led to a disappointing turnout for the much-anticipated Iowa Republican caucuses Monday night, where former President Donald Trump came out on top.
On Wednesday, 250 million Americans will experience below-average temperatures. The extreme cold will persist across much of the country through the end of the week.
