More than 160 million Americans are expected to face an unusually brutal winter storm from Friday, with heavy snows and freezing rains forecast.
The storm is expected to sweep through much of the United States, leaving "extremely dangerous" conditions in its wake as it tracks eastwards from the High Plains and Rockies, the National Weather Service (NWS) said.
It warned that the Arctic blast will bring sub-zero temperatures and wind chills, which "pose a life-threatening risk of hypothermia and frostbite to exposed skin".
US transportation officials, including airport authorities in several major cities, have warned of weekend travel disruption, delays and cancellations.
The winter storm is forecast to move slowly across the US, blanketing cities including Memphis, Nashville, Washington DC, Baltimore, Philadelphia and New York with snow.
