Temperatures have plunged to -29C in parts of the US as a deadly cold snap continued to grip much of the country.
Montana and South Dakota saw -29C during the day on Saturday while much of the Midwest was hit by temperatures around -17C to -7C.
Wind chill readings could drop as low as -46C in northwestern Minnesota, weather officials said.
So far, one person has died in North Texas after a pick-up truck went off of an icy bridge while four people have died of hypothermia in the San Francisco Bay area of California.
Half-a-dozen traffic-related deaths due to the weather were recorded in various states.
Icy conditions were expected to last through the weekend from Texas to Ohio to Tennessee, and Virginia officials warned residents of a major ice storm likely to take shape on Sunday, resulting in power outages and hazardous road conditions.
Weather forecasters said the powerful weather system has Virginia and the Mid-Atlantic states in its icy sights next.
Treacherous sections of Interstate 35 north of Dallas were closed for hours at a time as tractor-trailers had trouble climbing hills, wrecks occurred and vehicles stalled, authorities said.
Some 400 departing flights from Dallas, Fort Worth International Airport were cancelled on Saturday morning, the airport said.
About 3,330 passengers stayed overnight in the terminals.
"The weather, it's going to hold until probably after the weekend so I'm thinking I'm just going to hunker down," said Blaine Houserman, a stranded passenger.
More than 100,000 customers in the Dallas area were without power on Saturday, with about 7,000 in Oklahoma and thousands more in other states.
