The ice on the roads also shut down major highways, including cross-country Interstate 70, with sections of it closed in Colorado and Kansas.
In cities like Denver or Chicago, shelters have been opened to welcome people in need, to allow them to warm up and protect them from the risk of hypothermia.
Freezing in minutes
The storm is expected to last through the weekend before temperatures normalize in the middle of next week, the NWS said.
This type of storm is caused by a “low pressure bomb”, a collision between two air masses, one very cold from the Arctic and the other tropical from the Gulf of Mexico, aggravated because the atmospheric pressure dropped very quickly, in less than 24 hours. .
Until then, “if you must travel or be outdoors, prepare for extreme cold by wearing multiple layers of clothing and covering as much skin as possible,” the service wrote Saturday. “In some places, being outside could cause frostbite in a matter of minutes.”
Forecast strong winds, gusting to over 95 km/h, could cause further damage, including trees falling onto power lines.
Canada was also affected by the storm and all provinces had weather alerts.
Hundreds of thousands of people lost power in Ontario and Quebec, and airports in Vancouver, Toronto and Montreal were affected by flight cancellations.
Passengers on several stopped trains in Ontario report having been in the carriages for up to 18 hours due to extreme weather conditions.