Hundreds of schools across the Northeast were closed Monday after an unseasonably early storm dumped up to 30 inches of heavy, wet snow that snapped power lines and left utilities struggling to restore service to millions of customers.

By late Sunday, the number of outages had dipped to below three million and continued falling. But officials in some states warned that it could be days or even up to a week before residents and businesses have power again, even though utility companies have brought in additional crews and are working around the clock.

Concerns over youngsters' safety has prompted some communities to cancel or postpone Monday's Halloween trick-or-treating.