An Arctic front menaced the West and Northern Plains with killer cold and blowing snow yesterday, and forecasters warned farmers, stranded truck drivers and strained power companies to brace for more this weekend.

"There's no place to park. No place to stand. People are just trying to stay warm. Their trucks are frozen up. It's a terrible day, I can tell you that," said Darrell Kruljac, who owns a truck stop in Rock Springs, Wyo.

Drivers jammed his and other truck stops in Wyoming, waiting for a snowy 100-mile stretch of Interstate 80 to reopen as the wind chill reached 77 below zero.

The combined effect of the wind and cold was expected to drop the wind-chill index as low as 60 below in Minnesota and the Dakotas, the National Weather Service said. The wind chill made it feel like 75 below at Livingston, Mont., on the day before winter officially begins.

"The system will modify early next week, but until then it will be just brutally cold -- stiff winds, and wind chills well below zero," said David Wert of the weather service's office in Norman, Okla.

The cold trailed a snowstorm that arrived Tuesday from Canada. Together, they brought an early Christmas vacation for many students; threatened wheat, apple and other crops, and pushed electricity demand to record levels.

The storm system was blamed for at least 12 deaths since Tuesday in California, Oklahoma, Oregon and Washington.

Record lows Thursday included 26 below zero in Casper, Wyo.; 25 below in Great Falls and Helena, Mont.; 22 below in Billings, Mont.; 11 at Olympia, Wash., and Eugene, Ore.; 14 at Seattle; 15 at Astoria, Ore., and 23 at Sacramento, Calif.

Temperatures dived into the 40s in Los Angeles and single digits in Oklahoma.

The highest temperature predicted for Montana yesterday was 2 below at Libby, in the northwestern corner of the state. Most of Montana faces lows ranging from 10 to 40 below zero through Monday.

Blowing snow and freezing temperatures stranded about 400 passengers on 10 Greyhound buses in Salt Lake City overnight, company spokesman George Gravley said in Dallas.

Classes were canceled in North Dakota, southern Idaho and parts of Washington state and New Mexico.

"Puget Power is fighting a losing battle," said Tim Ortner, a sheriff's deputy in Whatcom County on the Canadian border. "Wind is just ripping up trees all over the county. They can't keep up with it."

Farmers dragged out their winter arsenal of frost- and snow-fighting equipment.

"There is the potential for real doom and gloom," said Bob Perkins of the Riverside County Farm Bureau in California. "They are using orchard heaters, helicopters, wind machines and irrigation to prevent damage."