NASSAU, Bahamas — Bahamians rescued victims of Hurricane Dorian with jet skis and a bulldozer as the U.S. Coast Guard, Britain’s Royal Navy and a handful of aid groups tried to get food and medicine to survivors and take the most desperate people to safety.

Airports were flooded and roads impassable after the most powerful storm to hit the Bahamas in recorded history parked over Abaco and Grand Bahama islands, pounding them with winds up to 185 mph and torrential rain before finally moving into open waters Tuesday on a course toward Florida.

At least 20 deaths were reported in the Bahamas, with the full scope of the disaster still unknown.

The storm’s punishing winds and muddy brown floodwaters destroyed or severely damaged thousands of homes, crippled hospitals and trapped people in attics.

“It’s total devastation. It’s decimated. Apocalyptic,” said Lia Head-Rigby, who helps run a local hurricane relief group and flew over the Bahamas’ hard-hit Abaco Islands. “It’s not rebuilding something that was there; we have to start again.”

She said her representative on Abaco told her there were “a lot more dead,” though she had no numbers as bodies being gathered.

The Bahamas’ prime minister also expected more deaths and predicted that rebuilding would require “a massive, coordinated effort.”

“We are in the midst of one of the greatest national crises in our country’s history,” Prime Minister Hubert Minnis said at a news conference. “No effort or resources will be held back.”

With a now-distant Dorian pushing its way up the Southeastern U.S. coast, menacing Georgia and the Carolinas, many people living in the Bahamas were in shock as they slowly came out of shelters and checked on their homes.

In one community, George Bolter stood in the bright sunshine and surveyed the ruins of what was once his home. He picked at the debris, trying to find something, anything, salvageable. A couple of walls were the only thing left.

“I have lost everything,” he said. “I have lost all my baby’s clothes, my son’s clothes. We have nowhere to stay, nowhere to live. Everything is gone.”

The Bahamian government sent hundreds of police officers and marines into the stricken islands, along with doctors, nurses and other health care workers, in an effort to reach drenched and stunned victims and take the full measure of the disaster.

“Right now there are just a lot of unknowns,” Parliament member Iram Lewis said. “We need help.”

Five Coast Guard helicopters ran near-hourly flights to the stricken Abaco, flying more than 20 injured people to the capital’s main hospital. British sailors were also rushing in aid. A few private aid groups also tried to reach the battered islands in the northern Bahamas.

“We don’t want people thinking we’ve forgotten them. … We know what your conditions are,” Tammy Mitchell of the Bahamas’ National Emergency Management Agency told ZNS Bahamas radio station.

With their heads bowed against heavy wind and rain, rescuers began evacuating people from the storm’s aftermath across Grand Bahama island late Tuesday, using jet skis, boats and even a huge bulldozer that cradled children and adults in its digger as it churned through deep waters and carried them to safety.

One rescuer gently scooped up an elderly man in his arms and walked toward a pickup truck waiting to evacuate him and others to higher ground.

Red Cross spokesman Matthew Cochrane said more than 13,000 houses, or about 45% of the homes on Grand Bahama and Abaco, were believed to be severely damaged or destroyed. U.N. officials said more than 60,000 people on the hard-hit islands will need food, and the Red Cross said 62,000 will need clean drinking water.

“What we are hearing lends credence to the fact that this has been a catastrophic storm and a catastrophic impact,” Cochrane said.

Lawson Bates, a staffer for Arkansas-based MedicCorps, flew over Abaco and said: “It looks completely flattened. There’s boats way inland that are flipped over. It’s total devastation.”

The Red Cross authorized $500,000 for the first wave of disaster relief, Cochrane said. U.N. humanitarian teams stood ready to go into the stricken areas to help assess damage and the country’s needs, U.N. spokesman Stéphane Dujarric said. The U.S. government also sent a disaster response team.

Abaco and Grand Bahama islands, with a combined population of about 70,000, are known for their marinas, golf courses and all-inclusive resorts. To the south, the Bahamas’ most populous island, New Providence, which includes the capital city of Nassau and has over a quarter-million people, had little damage.

The U.S. Coast Guard airlifted at least 21 people injured on Abaco. Choppy, coffee-colored floodwaters reached roofs and the tops of palm trees.

“We will confirm what the real situation is on the ground,” Health Minister Duane Sands said. “We are hoping and praying that the loss of life is limited.”

Sands said Dorian rendered the main hospital on Grand Bahama unusable, while the hospital at Marsh Harbor on Abaco was in need of food, water, medicine and surgical supplies. He said crews were trying to fly out five to seven kidney failure patients from Abaco who had not received dialysis since Friday.

The Grand Bahama airport was under 6 feet of water.