(CNN) - Hours before the Gwilliam family would leave the Hawaiian island of Kauai, they became stranded.
According to CNN affiliate KHNL, a deluge washed out a bridge, cutting the San Diego family's vacation rental off from safety.
"We tried not to let the kids see, but I was terrified," Erin Gwilliam, the mother, told KHNL.
But a nearby resident and good Samaritan approached in his boat and helped the family escape.
Their knight in a shining wetsuit? None other than surfing legend Laird Hamilton.
The famous big wave surfer has spent days coordinating rescues after severe rain struck last weekend, causing mudslides and power outages on the island of Kauai, where he lives. The resulting floodwaters have forced hundreds of people to evacuate.
In an interview Thursday, Hamilton sheepishly told CNN he's coordinated or conducted more than 75 rescues in floodwaters near his Kauai home, but he's not asking for credit.
"If you have compassion, this is what you do," Hamilton said. "These are opportunities to make a difference, when it really counts."
Over 400 people have been airlifted from Kauai since Monday, according to County Mayor Bernard P. Carvalho Jr. The island is particularly vulnerable, because the ground has become heavily saturated from the record-breaking rainfall of more than 30 inches.
Rescues weren't limited to people
Hamilton said the boat launch at his home is on the high side of the flood plain, which enabled him to continue the rescues, even as other boat launches across the island remained submerged.
"It allowed me to have access to the water," he said. "I was able to support farmers, help some people off their roofs and get them what they need."
The surfer has been getting up at 4 a.m. each day, working to help as many people in remote areas as he could before sundown, according to a spokeswoman for Hamilton.
Hamilton also rescued 15 girls from the home of fellow surfer Leila Hurst, and lent his boat launch to members of the National Guard, who used the location as a departure point for their own rescue operations.
The rescues weren't limited to humans: Hamilton and his friends also rescued approximately 80 bison they found in the flood plain, spread out to different spots around town, he said. Some were even standing on the reef.
"We were just going around in boats, tying them and towing them, trying to get them back into pasture," Hamilton said.
The threat isn't over
Flooding is not unusual for the area, Hamilton said, but the weekend's rainstorms were unparalleled. "People don't know the level of intensity of what's happened here," Hamilton said. "There are people who have lost everything."
"The power, the length and the strength of this: It's unlike anything that I've ever seen."
The National Weather Service has issued a flash flood watch for all the Hawaiian islands through Friday afternoon.
Hamilton said it's the Hawaiian residents' resilience and unity that helps them persevere in difficult times.
"In Hawaii we have a word called 'ohana.' It means family," Hamilton said. "Family and friends banding together. It's a pretty wonderful thing. This would have been much worse had we not all banded together here. That's ohana."
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