US south faces possible tornadoes as north braces for winter blast and rain

Tornado warnings issued in Alabama and Louisiana as rare blizzard conditions hit Pacific north-west

Millions of people across the US are facing extreme weather this week as forecasters warn of strong storms in the west, the threat of tornadoes forming in the south, and a winter blast that may produce widespread flooding in the east.

Widespread hazardous weather impacts are expected for the eastern third of the US," the National Weather Service (NWS) said on Tuesday, adding that flood risks extended from the Florida Panhandle up to Maine. The downpours will be accompanied by widespread strong winds gusting up to 50mph.