LAPORTE, Ind. - Kate Ergang wasn't worried when two jackknifed semi-tractors trapped her and a friend on an Indiana highway in a blizzard. They had eaten dinner already and had blankets and pillows in the car. They talked, listened to their iPods, and dozed off.

But the May college graduate had a few minutes of panic Monday morning when she awoke and realized that nearly 12 hours later, they were still in the same spot.

More than 100 vehicles were stuck Monday on Indiana's snow-covered highways. Strong winds and blowing snow hampered snowplow drivers' efforts to free them, but most motorists had been rescued safely by early afternoon, said Beth West, assistant director of LaPorte County 911. A few were still stuck in drifts Monday evening, with plows trying to reach them.

The wind and heavy lake-effect snow were part of a slow-moving storm that has been crawling across the Midwest since Friday night.

At least 15 deaths have been attributed to the storm, which dumped nearly 2 feet of snow in parts of Minnesota and Wisconsin before moving into Michigan and Indiana. Monday, it stretched farther east, with snow in parts of Ohio, Pennsylvania, and New York.

Up to 16 inches of snow fell in northwest Indiana, where 70 drivers got stuck in drifts on a section of Indiana Route 2 in the Valparaiso area.

Indiana State Police Lt. Lou Brown said some people made the situation worse by driving on roads that were closed or abandoning vehicles that got stuck. "People would get into a snowdrift and couldn't go anywhere, so they'd just leave the vehicle to get out of the weather," he said. "It just plugs things up and then snowplows can't get around them."

Eight people in four states, including Indiana, died in traffic accidents related to the storm, and a 79-year-old man snow-blowing the end of his driveway in western Wisconsin was killed when a plow backed into him. Five more died after shoveling or blowing snow, and Kenneth Swanson, 58, of rural River Falls, Wis., died when a metal shed collapsed from the heavy snow, pinning him under debris and about 3 feet of snow.

Along with the wind and snow, the upper Midwest has been gripped by bone-chilling cold brought by arctic air that swept in behind the storm. Wind chills were below zero in many places Monday, and schools in Indiana, Michigan, Wisconsin, and other states shut.

But the 12-degree temperature didn't stop hundreds of fans from lining up hours before free tickets to Monday night's football game between the Minnesota Vikings and the New York Giants became available at Ford Field. The game was moved to Detroit after the Minneapolis Metrodome's inflated roof collapsed Sunday under the weight of heavy snow.

In Minneapolis, stadium officials were trying to repair the roof in time for the Vikings' next home game, next Monday against Chicago.