New blasts of polar cold hit the Midwest yesterday, sending the wind chill factor near 100 below zero in northern Minnesota and dumping wind-driven snow on Indiana, Ohio and southern Michigan, according to the National Weather Service.

The arctic chill and strong winds have taken at least 251 lives this winter, already reaching the number predicted for the whole season, through March. New record cold temperatures were expected to drive from the Midwest to hit the East last night and today.

"It is one of the most severe outbreaks of cold weather mid-America has experienced since the 1800s," said Nolan Duke of the National Weather Service.

Wind chill readings lower than 20 below zero were recorded yesterday in states from Minnesota to Texas, from Montana to Ohio. Blizzard warnings were in effect across Michigan and Indiana as more snow--up to 11 inches in places--was dumped on top of last week's two snowfalls.

Chicago reported a wind-chill of minus 67 yesterday. The city's Park District opened up its field houses to refugees from the cold, and the Chicago Housing Authority set aside 100 apartments for people who might need temporary shelter.

In Ames, Iowa, firemen working in temperatures of 16 below zero with 30-mph winds fought 18 hours to control a fraternity house fire. Ice was so thick the fire equipment froze in place and a huge crane had to be used to break it loose.

Parts of the Sun Belt seemed like the Frost Belt. Freezing rain closed many highways in northern Georgia, and snow fell in the Texas Panhandle. More than 120,000 people remained without power in Alabama, Georgia and North Carolina.

Crops were severely damaged, including $4 million in damage to dormant peach trees in southern Illinois.

In Florida, the freeze has brought new damage to the state's citrus crop, in addition to the $500 million in damage already reported.

The controlling air currents that have caused the record cold weather have been dubbed "the Siberian Express" by one weather service forecaster, because the wind currents drive across from Siberia into Canada before diving down toward the middle of the United States.

"It just sits up there in the total darkness of the Arctic , getting colder and colder, then wallops us," said Duke.

Oddly, the same controlling air currents--called the jet stream --that have brought the cold are expected to jump farther south and bring abnormally warm temperatures to the middle of the country this week.

That shot of warm will be followed again by another jet stream shift, and more cold next week, said Steve Flood of the National Weather Service's long-range forecasting office in Washington. The changing weather systems are shifting "like a roulette wheel," making the weather difficult to predict, Flood said.

The high-altitude jet stream controls trends in the continent's weather as it passes across the hemisphere in long continent-wide waves. In the current cold snap, it is entering the continent across Canada, then dipping down into the United States with near-zero temperatures