ARLINGTON, Va. − A wall of snow, ice and rain was sweeping across the Northeast on Thursday, the first in a series of storms forecast to wallop much of the nation's northern tier over the next several days.

Thunderstorms brought heavy rains and caused flash flooding in portions of West Virginia, while a wintry mix coated trees and roads in several states.

In portions of Indiana, southern Michigan, Ohio and Pennsylvania, residents and storm spotters reported seeing “thunder ice” — freezing rain accompanied by flashes of lightning in the unstable air.

Residents and storm spotters in portions of Indiana, southern Michigan, Ohio and Pennsylvania reported the unusual mix of freezing rain accompanied by flashes of lightning in the unstable air.