https://www.bbc.com/news/articles/c0kvlkvzdgzoSevere winter storm puts much of US on high alert
58 minutes ago
Tens of millions of Americans are bracing for a huge winter storm that could bring the heaviest snowfall and coldest temperatures in over a decade.
The storm, which started in the middle of the US, will move east in the next couple of days, the National Weather Service (NWS) said.
A state of emergency has been declared in the states of Kentucky and Virginia, and parts of the US unaccustomed to severe cold, including Mississippi and Florida, have been warned to expect treacherous conditions.
Forecasters say the extreme weather is being
caused by the polar vortex,
an area of cold air that circulates around the Arctic.
"For some, this could be the heaviest snowfall in over a decade," the National Oceanic and Atmospheric Administration said.
AccuWeather forecaster Dan DePodwin said: "This could lead to the coldest January for the US since 2011."