Paul Weismann got the call for help Monday night at his home in Connecticut. By Tuesday afternoon, he was flying to Puerto Rico on his personal plane, with food, water, and power generators as his passengers.

“You fly over Puerto Rico on the way to the airport, and you see the place is wrecked,” Weismann told The Daily Beast. At night, “a few streets and highways are lit up, because of people and businesses with generators. But the rest of the island was just pitch black.”

After landing on the island destroyed by Hurricane Maria last week, Weismann reloaded his plane—this time with young children, mothers, and senior citizens—and took off for the U.S. mainland.

Weismann isn’t a professional rescue pilot though. He’s a Connecticut-based investor working with Patient Airlift Services (PALS), a network of volunteer pilots. PALS mobilized pilots from across the U.S. to help Texas, Florida, and now Puerto Rico and the U.S. Virgin Islands this hurricane season.

“You name it, we’ve done it,” said Eileen Minogue, the executive director of PALS. “We literally jumped into the deep end together to provide disaster relief and it just hasn’t stopped. We’ve been working for 30 days in a row right now pretty much round the clock just trying to provide support first in Houston and now in the islands.”

Her group, which usually provides airlift relief support within the United State’s northeast region, has partnered with other nonprofits to serve hurricane-stricken regions in Texas, Florida, and now the Caribbean. Since Maria hit, PALS has sent volunteer pilots to Caribbean islands like Puerto Rico daily, bringing satellite phones, water filters, generators, tarps, hammers, and medical supplies.

Pilots flew to Puerto Rico at their own risk; the storm disabled several traffic-control radars in San Juan.

“The hurricane knocked out all their radars, and I think most of their radio communications,” Weismann said. “They have technical teams, but the roads are all blocked, and the radars are up on the mountains.”

Much of Weismann’s work has been delivering supplies to air traffic controllers, so the airport can handle more planes. But he and other PALS pilots have also worked to evacuate some people to Florida, especially young children and senior citizens. Those chosen for evacuation are vetted through FEMA or other philanthropic groups on the ground.

Bob Lambert is a pilot from Michigan and has flown rescue missions for the past 10 years. He said he recently evacuated around 20 people, including children and their chaperones, from St. Thomas after flying rescue workers to the island.

“What becomes a little difficult mentally when you evacuate people, is deciding who really needs to go first,” he said. “That’s always a tough one mentally for me… That’s the emotional drain, making sure the people are safe and doing the best you can for the people.”

On Thursday morning, Weismann had evacuated 16 people, and was flying to Dominica, where he planned to evacuate more. Sometimes, as was the case with four mothers and their young children, Weismann coordinated with families to plan evacuations in advance. But spotty post-hurricane cellphone service meant that some planned evacuations fell through.

“People are contacting me asking if I can bring people out,” he said. “These contacts try to get in touch with people, telling them to get to the airport at the agreed time and find me. But they can’t get ahold of anybody because the phones are so terrible and spotty. People’s phones are going dead and can’t be recharged because they have no power.”

Fortunately, communications are still working from the air. Lambert said the only difference between flying to a storm-ravaged area and flying under normal conditions is that pilots need to carry extra fuel for the plane in case they receive incorrect information about landing conditions and have to turn back.

“It’s just human nature to try and help,” Lambert said. Small aircraft like those he and fellow PALS volunteers fly are “not a long-term necessity but the ability to react immediately and get on station quickly and land at small airports… we can literally respond in minutes or hours given the large number of airplanes that are willing to do this.”

Minogue said PALS expects to continue their efforts in Puerto Rico for the next four to six weeks.

“It just has escalated,” she said. “The 150 flights that we did in Harvey was a piece of cake compared to what we’re having to do in the islands.

Weismann said with increased demand has come a flood of volunteers.

“There’s hundreds of people coming out of chartered airlines,” Weismann said. “And firefighters, park service workers, forestry workers, rangers, and police. I saw a lot of FDNY there stacked up, ready to go inland and deploy. It was pretty moving to see what’s going on.”