'Polar Express' blast hits half the US as millions are warned to prepare for the worst storm in a decade with temperatures dropping to MINUS 40

By ASSOCIATED PRESS

A wintry storm pushing through the western half of the country is bringing bitterly cold temperatures that prompted safety warnings for residents in the Rockies and threatened crops as far south as California.

The jet stream is much farther south than normal, allowing the cold air to push in from the Arctic and drop temperatures by 20 to 40 degrees below normal levels, AccuWeather meteorologist Tom Kines said on Tuesday.

Areas of Montana and the Dakotas were forecast to reach lows in the minus-20s, while parts of California could see the thermometer drop to the 20s.

Commuters creep along the snowy highway in St Louis Park, Minnesota today as weather conditions were set to get worse later this week

Olivia Kumi braved the wintry weather by walking to work on Wednesday in Brooklyn Park, Minnesota as it turned bitterly cold following a huge storm system descending on the country

Brittany Katalenas braves snowy conditions on her walk to work in Boulder, Colorado as sub-zero temperatures set in

Sam Flaifel, left, Dave Warner, center, and Pat Riestenberg, clear snow from 400 cars in Brooklyn Center, Minnesota today. A wintry storm pushing through the Rockies and Midwest is bringing bitterly cold temperatures and treacherous driving conditions

The icy, 'Polar Express' blast was expected to be followed by another one later in the week, creating an extended period of cold weather that hasn't been seen since the late 1990s, meteorologists said.

Officials warned residents to protect themselves against frostbite if they are going to be outside for any length of time.

Snow falls on Monday afternoon in Shoreview, Minnesota as a storm hit 24 states

A tanker truck is tended to by firefighters after sliding off the snowy highway near mile marker 48 on Interstate 90 in Piedmont, South Dakota

A Department of Transportation plow clears snow from the northbound lane of Highway 85 near Jay Em, Wyoming

The storm hit the northern Rockies on Monday and Tuesday, dumping up to 2 feet of snow in the mountains and in Yellowstone National Park.

Snow and ice created hazardous driving conditions throughout the West, and were a factor in a four-vehicle crash in central Montana that killed 21-year-old Chelsea Stanfield of Great Falls. Authorities said Stanfield was driving too fast for the conditions. The weather also closed a stretch of Interstate 90 on Tuesday between Sheridan and Buffalo, Wyoming.

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