Storm threatens Thanksgiving travel
A severe storm has been blamed for up to a dozen deaths in the US and could threaten travel for millions over the approaching Thanksgiving holiday.
The icy storm started in the western states and has caused at least 10 fatal road crashes.
Hundreds of flights in Texas were cancelled amid freezing rain, which is expected to move east this week.
The National Weather Service (NWS) predicts heavy rain may delay travel for Thursday's Thanksgiving holiday.
'A flight nightmare'
Deaths from weather-related accidents were reported in the US states of Oklahoma, Texas, New Mexico and California.
Three members of singer Willie Nelson's band were reported injured in a Texas bus accident during heavy rains on Saturday. Mr Nelson was not aboard at the time.
Oklahoma received up to 10in (25.4cm) of snow, while weather warnings were issued for Arkansas on Monday as the weather system moved east across the nation.
Forecasters predict that strong winds and icy conditions across portions of the US on Tuesday and Wednesday - two of the busiest travel days of the year - could make Thanksgiving commutes dangerous.
More than 43 million Americans are expected to travel at least 50 miles (80.5km) for the holiday, while three million are scheduled to fly, according to the American Automobile Association.
Colder-than-usual temperatures are currently expected in the north-east, and could bring snow to the New England states, Pennsylvania, and New York on Wednesday.
"If the storm hugs the coast and develops to its full potential, it could be a flight nightmare, not only for travellers in the East, but also throughout the nation," AccuWeather.com's chief operating officer Evan Myers told NBC News.
Thanksgiving Day celebrates the harvest and blessings of the past year.
It has been marked for hundreds of years, and is generally thought to commemorate a 1621 harvest feast the US Pilgrims shared with Indians after settling at Plymouth, in what is now Massachusetts.
The modern festival sees millions of people travel to be with family, eat turkey feasts, watch NFL football matches and - in recent years - plan or even begin their assault on the holiday sales.