A blizzard fanning snow into 8-foot drifts virtually shut down Minneapolis-St. Paul and other major cities across the Midwest yesterday and forced thousands of highway travelers to seek refuge in churches, armories and libraries.

Flooding forced more evacuations in northern Louisiana, where 1,900 homes were under water and at least 100 roads were closed, but the sun was peeking through in places that had been deluged with as much as 17 inches of rain.

Some evacuees began returning to flood-ravaged areas in northern Mississippi, but rising water downstream threatened more evacuations later this week.

Since Christmas Eve, storms have been blamed for at least 27 deaths, mostly west of the Mississippi and mostly in traffic accidents.

The new snowstorm, worst of the season in many cities, spared hard-hit Denver, where a third runway was opened at Stapleton International Airport. But snow ranging in depth from 6 inches to almost 2 feet moved through eastern Colorado and across western Kansas, Nebraska, eastern Iowa, southeastern South Dakota, southern Minnesota, northwestern Wisconsin and northern Michigan.

Power went out in thousands of homes, with the wind-chill factor plunging as low as 45 degrees below zero and snow falling as fast as 3 inches an hour.

Motorists were put up for the night in emergency shelters in many communities, and motels along interstate highways were filled, with people often sleeping in lobbies and meeting rooms.

By contrast, at least 16 midwestern cities -- including Chicago, Milwaukee and Ann Arbor, Mich. -- posted record warm temperatures for the day, with readings in the high 50s and 60s.

In Chicago, 80-mph gusts whipped up 15-foot waves on Lake Michigan and pitched six 150-pound steel beams 40 stories from a high rise under construction. Two men were injured by falling boards. "These things are coming down like toothpicks," a policeman said.

Authorities urged people not to travel in Minneapolis and St. Paul, where 15 inches of snow fell, drifts were as high as 10 feet and the Postal Service stopped deliveries. The airport, closed for about 20 hours, reopened late last night.

In Delano, Minn., Dr. Craig Christianson made a house call on skis to deliver a baby in a blizzard. He arrived about 2 a.m., two hours ahead of the baby. A deputy sheriff with a snow-plow escort stood by in case of emergency.

Minneapolis artist James Meger said that a bus carrying his mother to Canby during the night stalled near Franklin in the west-central part of the state and that residents formed a convoy of pickup trucks to rescue the 30 passengers.

Drifts as high as 7 feet clogged streets in Sioux City, Iowa, and officials in Sioux Falls, S.D., recommended that no one travel on foot until the snow was cleared.

"Tell the people to take a vacation," said Rusty Kapela, a National Weather Service meteorologist in South Dakota, where as much as 17 inches of snow fell atop a heavy weekend accumulation. The Weather Service recommended no travel in 28 counties.

Between 600 and 700 stranded travelers were sheltered at an armory, a community building, a church and a large tavern in Colby, Kan., as snow whipped by winds closed a 250-mile stretch of Interstate 70 from Salina to the Colorado border.

In Lexington, Neb., about 300 spent the night at an armory, where National Guardsmen baked rolls and local restaurants opened to provide food. Two Lexington churches housed several hundred refugees.

Winds as high as 60 mph caused widespread power outages in Iowa's Quad Cities area. Most of Ida County and the towns of Whiting and Onawa also were without power. At Muscatine, Iowa, winds gusting to more than 90 mph toppled the transmission tower of two radio stations.

In western and north-central Kansas, utility officials said about 20,000 homes and businesses had no electricity and would likely be without power for two days.

In Monroe, La., where about 800 persons were evacuated earlier, officials said a sandbag levee was near the breaking point, and Guardsmen were called in to help move more families.

Joe Colson, director of the state's Office of Emergency Preparedness, said that, although rain has stopped, rivers were still rising in places.

"I understand they're comparing this with 1973, when we had over 20 parishes counties in a state of emergency," he said.