A massive rescue and relief effort is underway in the Bahamas where there is widespread devastation from Hurricane Dorian. At least 20 people were killed there. Thousands are stranded without shelter, clean water, or food – and the clock is ticking.

"CBS This Morning" lead national correspondent David Begnaud traveled to the hard-hit Abaco Islands, to get a firsthand look at the destruction. Getting a ride on a medevac plane, Begnaud and his crew touched down in the community of Treasure Cay, where a little more than a thousand people live.

At what's left of the airport, entire families with just the clothes on their backs were trying to evacuate.

The stories the locals shared were staggering.

"Never ever seen anything like this," said Stafford Symonette.

"This was just, just so far beyond anyone's imagination," said Nancy Albury.

"Everything's gone! Everything! Everything!" said one woman.

Survivors of Hurricane Dorian at what's left of the airport in Treasure Cay. CBS News

Shock and horror … those are some of the emotions people here are feeling as they begin to realize the devastating effects of Hurricane Dorian.

"The wind sounded like a huge tornado coming," said one boy, Noah.

Anton Russell recalled, "The next minute, the roof went off. We had to run to another house."

The Red Cross says nearly half of the homes on Abaco and Grand Bahama Islands were damaged or destroyed.

Nancy Albury was one of dozens of people at the airport desperately asking any pilots who landed there if she could get a seat off the island. Her home was in the nearby community of Man-o-War. She rode out the storm in her house.

"The house had broken up around us," she said. "And we cracked the door open and there was nothing left."

Santhia Gedeon was sitting with her three children on a slab of damaged cement inside of a heavily damaged, abandoned home near the airport. Someone had given her and her children bread and water bottles. Gedeon told Begnaud they wanted to go to Nassau.

The airport is also serving as a meeting place for relatives and co-workers. These families didn't know if their relatives survived. "I'm just happy to see 'em," said one survivor.

One 11-year-old boy was asked, "When you see what's left of your home, what do you think?"

"We gotta get out of here," he replied. "We can't live here. Like, we gotta go somewhere safe like in the States where they are no hurricanes or no tornadoes."

On Grand Bahama Island, three-quarters of the homes have been wiped out or are underwater. Landing at the airport there is currently impossible.

Just about everyone evacuated from the disaster zone is airlifted out to the capital of Nassau, which was not damaged by Dorian.

In Nassau, the emotional reunions continued through the night, as more people arrived from Abaco alive. All of the survivors sent there are triaged and sent to a hospital, or to find a place to sleep.

"It was a harrowing experience," said Brenee Crakes. "It's difficult even to try to put it into words, but it was just unparalleled."

In Nassau, Robert and Phyllis Cornea are seeking refuge. They say the Category 5 storm destroyed their home in Abaco, the island on which they lived for more than 50 years.

"All the buildings, all the main buildings. Gone," Robert told "CBS Evening News" anchor Norah O'Donnell. "Everything. Gone."

Phyllis said all she had left were the clothes on her back: "I've been in this four days."

Restoration Abaco co-founders Heather Hunt and Sandra Cooke described the desperation. "The looting has begun, and these people are armed," Cooke said. "They're going after homes that are still intact that have generators maybe, food. It's bad."