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.

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.

Winter weather advisories for all 21 counties are in effect with ice and up to 3 inches of snow possible in spots.