America on HEAVY SNOW alert for Winter Storm Gerri as COLDEST blast in a year hits

Freezing air surging southwards will crash into warmer air from Mexico driving a polar onslaught that will unleash a freak bout of ‘desert snow’.

The US National Weather Service (NOAA) has a raft of warnings across the country as the danger from heavy snow, blizzards and floods reaches crisis point.

A spokesman said: “A disturbance moves inland across the Desert Southwest and this brings valley rain and mountain snow across Arizona and New Mexico.

“Meanwhile, an Arctic front drops southward from Canada on Wednesday, and this will herald the arrival of the coldest temperatures so far this season for the Northern Plains.

“This cold airmass will continue settling southward through the end of the week. The combination of this front and the storm system from the southwestern US will eventually result in a much larger low-pressure system developing over the Southern Plains by the end of the week.”

Storms have ravaged swaths of the US this week as a barrage of low-pressure cyclones barrelled in from the west and up the east coast.

Deadly winds killed at least three people while leaving hundreds of thousands of homes without power, according to The Weather Channel.

Churning tornadoes have unleashed mayhem through the Gulf Coast and south-eastern states, with high winds whipping across Texas, Louisiana, Mississippi, Alabama, Georgia, Florida and North and South Carolina.

Thousands of flights at the start of the week were cancelled with forecasters now warning blizzards will sweep America in the wake of the storms.

Weather Channel meteorologist Domenica Davis said: “The snow is not over, we have another system on the way arriving Friday night and this could bring some big-time snowfall totals.

“There will be heavy snow and strong winds and the rain-snow line will be further to the south. This is going to be a potentially a very big storm.

“It moves through Sunday, and travel conditions are going to be treacherous through the weekend. Yes, there could be upwards of a foot of snow.”

Huge swaths of the US are facing the wrath of Gerri which also threatens to pull in a plume of freezing Arctic air.

Storm Gerri has already smashed through north-western regions knocking out power and leaving some communities buried under inches of snow.

Central and eastern states are braced for the worst of the onslaught this weekend when thunderstorms could whip up crippling bouts of thundersnow.

A Weather Channel spokesman said: “Peak impacts in the central and eastern states will be Friday and Saturday.

“Low pressure will swing out into the Plains states on Thursday, and snow will develop in the cold air with some severe thunderstorms possible.

“The storm is expected to intensify Friday in the Mississippi Valley, then race into the Great Lakes and eastern Canada by Friday night and Saturday.”

The storm will be supercharged by a boost of tropical moisture flooding in from the Gulf of Mexico, he added.