Hurricane Dorian has unleashed rain, wind and flooding across the Bahamas.
Authorities urged people to find floatation devices and grab hammers to break out of their attics if necessary.
At least five deaths were blamed on the storm.
“We are in the midst of a historic tragedy,” Prime Minister Hubert Minnis said in announcing the fatalities.
He called the devastation “unprecedented and extensive.”
The fearsome Category 4 storm slowed almost to a standstill as it shredded roofs, hurled cars and forced even rescue crews to take shelter until the onslaught passed.
The deaths in the Bahamas came after a previous storm-related fatality in Puerto Rico. At least 21 people were hurt in the Bahamas and evacuated by helicopters, the prime minster said.
Forecasters warned that Dorian could generate a storm surge as high as 23 feet.
Meanwhile in the United States, the National Hurricane Center extended watches and warnings across the Florida and Georgia coasts. Forecasters expected Dorian to stay off shore, but meteorologist Daniel Brown cautioned that “only a small deviation” could draw the storm’s dangerous core toward land.
By 10 p.m. EDT Monday, the storm’s top sustained winds had fallen to 140 mph (220 kph), still within Category 4 range. It was still virtually stationary, centered just 25 miles (40 kilometers) northeast of Freeport — about the same distance from the city it had been at noon. Hurricane-force winds extended outward as far as 45 miles (75 kilometers) from the center
An advisory from the hurricane center warned that Florida’s east-central coast could see a brief tornado sometime Monday afternoon or evening.
A mandatory evacuation of entire South Carolina coast took effect Monday covering about 830,000 people.
A few hours later, Georgia’s governor, Brian Kemp, ordered mandatory evacuations for that state’s Atlantic coast, also starting at midday Monday.
Authorities in Florida ordered mandatory evacuations in some vulnerable coastal areas. North Carolina Gov. Roy Cooper warned his state that it could see heavy rain, winds and floods later in the week.
A hurricane watch was in effect for Florida’s East Coast from Deerfield Beach north to South Santee River in South Carolina. A storm surge watch was extended northward to South Santee River in South Carolina. Lake Okeechobee was under a tropical storm watch.
The Associated Press contributed to this article.