A powerful winter storm sweeping the United States this week could bring the coldest Christmas in 4 decades.
The cold wave, which experts say comes once in a generation, started in the Pacific Northwest on Thursday, before heading east where it will turn into a "bomb cyclone" on Friday.
More than 90 million people have been warned of severe weather in 37 states. 80 percent of them are expected to experience freezing temperatures several degrees below zero, including states as far south as Texas.
Dubbed Winter Storm Elliot, the arctic blast is expected to bring the Midwest's coldest Christmas since the late 1980s. Even the Sunshine State, Florida, is forecast to have its coldest holiday in 30 years. The storm is expected to bring strong winds and heavy snowfall, making travel conditions difficult on Christmas Eve.
Many airlines are offering passengers alternative flights to the areas expected to be most affected. Hundreds of flights from Denver to Chicago have been canceled.
In Denver the thermometer marked -26 degrees Celsius this Thursday while Chicago has been warned to prepare for heavy snowfall.