BOISE, Idaho (AP) — A Montana motorcyclist who was missing for five days after crashing along an Idaho mountain highway survived by drinking creek water until he was found, authorities say.

Zachary Demoss, 24, was badly injured in the crash but “was tough enough to hold out for five days on that mountain while he’d seen people walking by, trying to holler at them,” family friend Greg Common told Boise television station KTVB. Demoss’ shouting went unanswered until Common caught sight of him while searching five days after the Aug. 11 crash.

“It was surreal that we found him,” Common said. “Something just willed me to look right and there he was, laying right there by the river.”

Demoss had been riding his 2000 Kawasaki Vulcan motorcycle along Highway 12 with two other people. After the other travelers saw his motorcycle parked on the side of the highway, they stopped at the next turnout a few miles down the road to wait for him.

Demoss never arrived, so his companions went back to check on him, stopping at the trailhead where they had last seen his bike. Neither Demoss nor his motorcycle was there.

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Aly Phan, one of the motorcycle riders, later wrote on Facebook that Demoss was the most experienced rider in the group. Phan and the other biker decided Demoss hadn’t seen them pass him, and they assumed he had likely assumed they were missing and had turned back himself to look for them.

“We were low on gas and our back tire was starting to show threads so we couldn’t go further back down the highway to where we came from to search further without getting in a wreck or broke down,” Phan wrote.

After waiting for two hours at the trailhead and leaving a large note in the gravel of the pullout, they decided to continue ahead to the group’s next planned stop in Lolo, Montana.

They stopped at the first gas station and checked with every person they could, asking if anyone had seen a motorcyclist fitting Demoss’ description. They called his cellphone and checked with other friends and family members, and they had a friend come with a truck so they could begin searching along the pass. They searched until 4 a.m. but found no sign of Demoss.

The Idaho County Sheriff’s Office was notified of the missing man on Aug. 12. It used drones and a helicopter to search by air while deputies looked on foot along a 99-mile (160-kilometer) stretch of road. They also checked road condition cameras and worked with Demoss’ cellphone company to see if his phone was connecting to any towers in the region. They made plans to have divers check deep sections of the river where it runs alongside the highway.

But after finding no sign of the man over the next few days, the sheriff’s office said it would begin to scale back search efforts.

Still, Demoss’ family and friends continued to search on foot, walking for miles while scouring the roadside.

On the fifth day of the search, Common spotted him near a campground. Demoss was conscious but badly injured and had been drinking water from a creek to stay alive. Common used an emergency satellite communicator to send an SOS message, and first responders soon arrived to take Demoss by air ambulance to a hospital.

Demoss’ mother, Ruth Rickenbacher, called his rescue a miracle in a Facebook post.

“He’s ALIVE!!! We were so heartbroken this entire last week as we walked mile by mile until dark only to end the day on defeat,” Rickenbacher wrote. “His dad and I never stopped believing he would be found in any other way than alive. My son is just one of those men that have true grit.”

Demoss sustained multiple broken bones, a collapsed lung and several other injuries, Rickenbacher wrote, saying “it’s like he was shaken like a rag doll.”

Recovery will take a while, she said, thanking well-wishers for contributing to a GoFundMe fundraiser to help cover his medical bills.