At least 15 people are reported to have been killed as a result of hurricane Isabel.
Five and a half million homes and businesses have been left without power across the East Coast.
The worst damage was caused by winds and rains that downed tens of thousands of trees and pushed rivers and streams to record flood levels across a region already saturated with above-average rainfall.
Earlier, President George W Bush declared parts of the states of North Carolina and Virginia major disaster zones.
