Hurricane Dorian appears to have caused “unprecedented” devastation in the Bahamas, the country’s leader says.
The category five storm, the second-strongest Atlantic hurricane on record, remains “extremely dangerous”, said Prime Minister Hubert Minnis.
Some 13,000 houses are feared damaged or destroyed, according to the International Red Cross.
Pictures showed surging floodwaters, upturned cars and snapped trees.
Dorian is the most powerful storm to hit the Bahamas since records began and will later move “dangerously close” to the US east coast, according to forecasters.
It is moving with maximum sustained winds near 165mph (270km/h). A “life-threatening storm surge” could raise water levels by as much as 23ft (7m) in parts of Grand Bahama island, which is currently being pummelled by Dorian, said the US National Hurricane Center.
It said that only a slight deviation in the path of the storm could bring Dorian directly over Florida’s east coast, which is already expected to face life-threatening storm surges and dangerous winds over the next couple of days.
The US states of Florida, Georgia, North and South Carolina have all declared states of emergency.
What’s the latest from the Bahamas?
The storm is crawling over Grand Bahama at an extremely slow pace, having earlier made landfall on the Abaco islands, which are just to the east.
Both chains are in the north of the Bahamas archipelago. Grand Bahama, with a population of about 50,000, is only 100km (60 miles) east of West Palm Beach in Florida.
Dorian is travelling west at just over 1mph (2km/h), says the National Hurricane Center (NHC).
The NHC said the hurricane would “continue to pound Grand Bahama Island” through much of the day and evening on Monday.
There was little information overnight from the affected Bahamas islands amid power cuts and limited internet access.
But on Monday, Prime Minister Hubert Minnis said that reports from Abaco suggested the devastation was “unprecedented”.
The International Red Cross said that initial assessments showed Hurricane Dorian had caused “extensive damage”.
“As many as 13,000 houses could have been destroyed, there might no longer be any clean water readily available on Abaco because of storm surges flooding wells,” spokesman Matthew Cochrane told the BBC.
He said that aid workers were expecting there to be “significant humanitarian needs” in the Bahamas once the storm passes.
The UK Department for International Development said it was sending three humanitarian experts to the Bahamas.
The Abaco Islands are home to about 17,000 people. It is unclear how many residents ignored evacuation orders and pleas from officials to leave low-lying areas.
Latrae Rahming, a former aide to ex-PM Perry Christie, told the BBC it was as though a tornado had swept through Marsh Harbour on the Abacos, with a surge as high as a two-storey building bringing intense flooding.
He said he feared for one shanty town area that houses about 1,500 people.
One video as the storm hit the Abacos carried a desperate plea for help:
Severe flooding is being reported in parts of Grand Bahama, and local media report that the international airport is under water.
There has been no official confirmation of casualties but TV station Eyewitness News carried an interview with a grandmother who said her eight-year-old grandson had drowned on the Abaco Islands.