A powerful winter storm is sweeping across the U.S., bringing sub-zero temperatures, life-threatening wind chills and heavy snowfall.
The cold temperatures are causing disruptions to holiday travel.
In the Denver area, people woke up to temperatures around -15 degrees. More than 200 flights in and out of Denver International Airport Thursday were canceled.
There's concern that wind up to 30 mph could lead to wind chills as low as -40 degrees across the Intermountain West and northern and central Plains, according to the National Weather Service.
Chicago's temperature is expected to drop more than 30 degrees on Thursday to below zero. Chicago O'Hare International Airport had the most flight cancelations reported as of Thursday morning, according to flight tracking website FlightAware.com. More than 250 flights for Thursday were canceled at the airport.
The storm is also expected to hit areas that don't typically see extremely cold temperatures. The National Weather Service says Texas and the Gulf Coast will experience temperatures in the single digits and teens Thursday evening.
As the storm moves eastward, forecasters warn that snow squalls could lead to extremely hazardous travel conditions.
More than 112 million people are expected to travel between Dec. 23 and Jan 2, according to AAA. More than 100 million of those travelers plan to drive.
However, officials across the country encourage people to stay off the roads during dangerous conditions.