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.

The ingredients needed to create blockbuster Northeast winter storms historically align this month, all that’s needed is a storm to take the right track.

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.