THE MIDWEST: There was no school today in Lake Woebegon. In fact, with early morning wind chills of 70 below across much of Minnesota, Governor Arne Carlson closed all public schools in the state. A mass of arctic air has settled in over the region, bringing blizzard conditions that have shut most everything down. Gusting winds in the Dakotas have topped out over 50 mph, and conditions are nearly as bad in the plains and rolling hills of Iowa, where even the lightest dusting of snow is driven hard enough to create "whiteout" conditions. Even discounting wind chills -- which is not advised -- temperatures in many places may not break zero today, and are expected to dip again overnight. Across the upper Midwest, the snow is blowing over icy roads, creating treacherous driving conditions. Post offices, retail stores and schools have been forced to close their doors. Alaska, by contrast, is unseasonably warm today, with wind chills in Barrow a mere 10 below. The system will move east into lower Michigan and Ohio by this evening. Residents in Sault Ste. Marie, Michigan, the nation's second-snowiest city, are bracing for at least another foot of snow today. Despite the arctic conditions, some hardy Minnesota residents were undeterred: At the John Beargrease Sled Dog marathon in Grand Marais, Minnesota, racers were mushing onward, defying wind chills of 60 below.