Updated

With 25 percent of the homes in the Florida Keys feared destroyed, emergency workers Tuesday rushed to find Hurricane Irma's victims -- dead or alive -- and deliver food and water to the stricken island chain.

As crews labored to repair the lone highway connecting the Keys, residents of some of the islands closest to Florida's mainland were allowed to return and get their first look at the devastation.

"It's going to be pretty hard for those coming home," said Petrona Hernandez, whose concrete home on Plantation Key with 35-foot walls was unscathed, unlike others a few blocks away. "It's going to be devastating to them."

But because of disrupted phone service and other damage, the full extent of the destruction was still a question mark, more than two days after Irma roared into the Keys with 130 mph winds.

Brock Long, a Federal Emergency Management Agency administrator, said preliminary estimates suggested that 25 percent of the homes in the Keys were destroyed and 65 percent sustained major damage.

"Basically, every house in the Keys was impacted," he said.

Residents in the upper Keys were able to return home on Tuesday. Fox News interviewed residents who surveyed damage to their homes.

Clay Crockett, a resident in Key Largo, walked around his home and pointed to the knee-high water line on the outside. “See, the water line is right here, which means I’m going to be flooded inside here. Yep. I can tell I have flooding inside already.”

He looked into a window and said, “Oh my God.”

In Islamorada, a trailer park was devastated, the homes ripped apart as if by a giant claw. A sewage-like stench hung over the place.

Debris was scattered everywhere, including refrigerators, washers and dryers, a 25-foot (8-meter) fishing boat and a Jacuzzi. Homes were torn open to give a glimpse of their contents, including a bedroom with a small Christmas tree decorated with starfish.

One man and his family came to check on a weekend home and found it destroyed. The sight was too much to bear. The man told his family to get back in the car, and they drove off toward Miami.

Lisa Storey and her husband, who live in Key Largo, said they had yet to be contacted by the power company or by city, county or state officials. As she spoke to a reporter, a helicopter passed overhead.

"That's a beautiful sound, a rescue sound," she said.

Authorities stopped people and checked for documentation such as proof of residency or business ownership before allowing them back into the Upper Keys, including Key Largo, Tavernier and Islamorada.

The Lower Keys -- including the chain's most distant and most populous island, Key West, with 27,000 people -- were still off-limits, with a roadblock in place where the highway was washed out.

In Lower Matecumbe Key, just south of Islamorada, 57-year-old Donald Garner checked on his houseboat, which had only minor damage. Nearby, three other houseboats were partially sunk. Garner had tied his to mangroves.

"That's the only way to make it," said Garner, who works for a shrimp company.

Although the Keys are studded with mansions and beachfront resorts, about 13 percent of the people live in poverty and could face big obstacles as the cleanup begins.

"People who bag your groceries when you're on vacation -- the bus drivers, hotel cleaners, cooks and dishwashers -- they're already living beyond paycheck to paycheck," said Stephanie Kaple, who runs an organization that helps the homeless in the Keys.

Corey Smith, a UPS driver who rode out the hurricane in Key Largo, said it was a relief that many buildings on the island escaped major damage. But he said conditions were still not good, with branches blocking roads and supermarkets closed.

"They're shoving people back to a place with no resources," he said by telephone. "It's just going to get crazy pretty quick."

The Associated Press contributed to this report