Relief is on the way to the United States, which has seen days of life-threatening cold due to record low temperatures.
Temperatures are expected to rise to near normal in the Midwest by Thursday, and spring-like weather is expected in the east by the end of the week.
Temperatures in all or parts of each of the 50 states were below freezing at some point Tuesday, even in Hawaii, where it was minus six degrees Celsius on top of the state's highest mountain.
The cold that froze over midwestern cities such as Chicago and Minneapolis spread to the eastern part of the country Tuesday. It was minus 10 degrees Celsius in Washington, New York, Philadelphia and Boston, with the wind chill making it feel much colder.
Temperatures also reached record lows in the normally temperate south.
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The bitter cold shut down schools, disrupted train service, and led to the cancellation of thousands of flights. At least five deaths have been reported nationwide.
The frigid weather was caused by what meteorologists call a polar vortex -- a rotating mass of cold dense air that usually stays in place in northern Canada, but was pushed south by the jet stream.
Some information for this report was provided by AP and Reuters.