(CNN) --
A major winter storm ripping through much of the central and eastern United States is causing record temperature drops and harsh snow conditions that have resulted in flight cancellations, highway closures and several emergency declarations. state.
The storm is affecting nearly every state, with more than 100 million people in the country currently under winter weather and wind chill watches, in what the National Weather Service calls a "once-in-a-generation event."
Winter storm hitting the US hampers travel and brings record low temperatures
Children shovel snow from a sidewalk and driveway in Minneapolis on December 22.
(Credit: Abbie Parr/AP)
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Travelers arrive for their flights at O'Hare International Airport on December 22 in Chicago.
(Credit: Kamil Krzaczynski/AFP/Getty Images)
A person crosses the street after a lone motorist in Denver on December 22.
(Credit: David Zalubowski/AP)
Ice accumulates on a window in Oklahoma City on December 22.
(Credit: Bryan Terry/The Oklahoman/USA Today Network)
Miguel Salazar cleans sidewalks in Denver on December 22.
(Credit: Hyoung Chang/Denver Post/Getty Images)
Cots for people seeking shelter from the cold fill the catwalks of the Denver Coliseum on Wednesday, December 21.
(Credit: David Zalubowski/AP)
An Iowa Department of Transportation plow clears a highway in Iowa City on December 21.
(Credit: Joseph Cress/Iowa City Press Citizen/AP)
Greg Behrens tries to stay warm as he walks down a snow covered sidewalk in Des Moines, Iowa on December 21.
(Credit: Charlie Neibergall/AP)
Crews remove ice from a Southwest Airlines plane before takeoff in Omaha, Nebraska, on December 21.
(Credit: Chris Machian/Omaha World-Herald/AP)
Travelers arrive at the Minneapolis-Saint Paul International Airport.
(Credit: Alex Kormann/Star Tribune/AP)
Propane heaters next to pens at the Mission City Animal Shelter in Mission, Texas, on December 21.
(Credit: Joel Martinez/The Monitor/AP)
Snow blankets homes in Seattle on Tuesday, December 20.
(Credit: Daniel Kim/The Seattle Times/AP)