Freezing weather has gripped the United States, causing power outages, flight delays and even deaths.
Heavy snow and unseasonably cold air hit parts of the West and northern Plains. In Montana and North Dakota, temperatures dipped to nearly 30 degrees below zero Celsius.
On Saturday temperatures dropped below zero in the normally warmer southern states of Texas, Arkansas and Oklahoma. The cold air froze the wet snow that had blanketed much the region on Friday.
The ice knocked down power lines in some areas and at least 10 people have been killed so far in weather-related incidents.
Freezing temperatures even reached Las Vegas, Nevada. Forecasters say the city may see rare snow flurries before the weekend is out.
The storm also affected travel, causing hundreds of car crashes and forcing the cancellation of nearly 700 flights Friday, most of them from Dallas/Fort Worth International Airport. Officials say flights have now resumed.
The cold wave is spreading to the mid-Atlantic and northeastern states on Sunday.
Crowded urban areas on the East Coast, including Washington, Philadelphia, and New York are bracing for snow, sleet and ice.
Temperatures are expected to rise above freezing on Monday.
Some information for this report was provided by AP and Reuters.