Storms spawned at least one tornado, sent creeks over their banks and caused flash flooding Thursday in portions of West Virginia and Kentucky, while a wintry mix coated trees and roads in ice and even dropped “thunder ice” in several states.

A winter storm that brought snow, sleet and freezing rain to a large swath of the Midwest swept into the mid-Atlantic and Northeast on Thursday, causing treacherous travel conditions, prompting school delays and closures and potential power outages for millions of Americans.

Just as the Midwest and Northeast grapple with an ongoing winter storm, an even stronger one is on its way this weekend. Freezing rain is again a concern for many areas, but the major difference will be significantly heavier snowfall.