Hurricane Florence, which is nearing the US East Coast, could kill “a lot of people”, officials warn.
Federal Emergency Management Agency (Fema) administrator Brock Long said storm surges may bring catastrophic flooding to inland areas.
Though Florence has been downgraded to a category two storm with 105mph (165km/h) winds, Mr Long said it remained “very dangerous”.
He said “feet of rain not inches” would drench the Carolinas and Virginia.
Mr Long told Thursday morning’s news conference that while Florence’s wind speed had dipped, its wind field had expanded and total rainfall predictions were unchanged.
Floodwaters may rise up to 13ft (4m) as rivers see their flows “reversed”, meteorologists have warned.