BOISE, Idaho – A Montana motorcyclist who was missing for five days after a crash on an Idaho mountain road survived by drinking creek water until he was found, authorities say.

Zachary Demoss, 24, was seriously injured in the crash but “was strong enough to last five days on the mountain while watching people walk by trying to yell at them,” family friend Greg Common told Boise television station KTVB. Demoss’s screams went unanswered until Common found him during a search five days after the crash on Aug. 11.

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

Demoss was traveling on Highway 12 with two other people on his 2000 Kawasaki Vulcan motorcycle. When the other travelers saw his motorcycle parked on the side of the road, they stopped at the next exit a few miles away to wait for him.

Since Demoss never arrived, his companions went back to check on him and stopped at the trailhead where they had last seen his bicycle.

Neither Demoss nor his motorcycle were there.

Aly Phan, one of the motorcyclists, later wrote on Facebook that Demoss was the most experienced rider in the group.

Phan and the other biker concluded that Demoss had not seen them pass him and assumed that he had probably assumed they were missing and turned around to look for them himself.

“We were low on gas and our rear tire was starting to crack, so we couldn’t continue on the highway back to our origin to continue searching without crashing or breaking down,” Phan wrote.

After waiting two hours at the trailhead and leaving a large note in the gravel of the exit ramp, they decided to move on to the group’s next planned stop in Lolo, Montana.

They stopped at the first gas station and asked as many people as they could if anyone had seen a motorcyclist matching Demoss’ description.

They called him on his cell phone and checked with other friends and family members. They also had a friend come with a truck so they could start 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 August 12. It used drones and a helicopter to conduct an aerial search while officers searched a 99-mile stretch of road on foot.

They also checked road condition cameras and worked with Demoss’s cell phone provider to see if his phone had a connection to any cell towers in the area. They planned to have divers examine the deep sections of the river along the highway.

However, after no trace of the man was found in the following days, the sheriff’s office announced that search efforts would be scaled back.

Nevertheless, Demoss’ family and friends continued their search on foot, walking for miles and searching the side of the road.

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

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

“He is alive!!! We were so heartbroken all last week as we ran mile after mile until dark only to end the day in defeat,” Rickenbacher wrote. “His father and I never stopped believing that he would be found in some way other than alive. My son is just one of those men who has true perseverance.”

Demoss suffered multiple broken bones, a collapsed lung and several other injuries, Rickenbacher wrote. “It’s as if he had been shaken like a rag doll,” he said.

Recovery will take some time, she said, thanking well-wishers for their contributions to a GoFundMe fundraiser to pay his medical bills.