Track the winter storm as it's forecasted to bring heavy snow and extremely cold weather to the U.S., reaching millions from the southern U.S. to the Northeast.

Winter storm warnings and advisories extended from Montana to Ohio, the National Weather Service said. Forecasters warned there could be airport delays and slowed traffic with snow falling at more than an inch per hour in some areas. More than 100 homes have been damaged after a tornado touched down in a residential area outside Houston.