A strong push of Arctic air moved into the Midwest on Tuesday causing snow and falling temperatures. Thousands of people lost power, and some government offices, schools and highways closed because of snow. The cold air and wind gusting as high as 70 mph headed into the Midwest, where fog created problems for air travel Tuesday in Chicago. About 200 flights had been canceled by afternoon at O’Hare Airport. Temperatures surged into the 40s early in the day but by evening snow was falling and temperatures had plunged to the teens at O'Hare. Temperatures overnight in the "Windy City" were expected to drop to 0 with wind chills to 25 below.