A family in Hawaii is desperately searching for a 27-year-old man who set out on a relatively easy hike more than a week ago and hasn't been heard from since.
Kyle Brittain was staying with his father on Hawaii's Big Island when he decided to spend Aug. 30, the last day of his trip, hiking Waipio Valley on a trail dubbed the "Z Trail" due to the shape of the path.
"He called me and said, 'I want to go up the Z Trail by myself,' and I said, 'I don't know if I like that idea,'" Brittain's father, Steve Brittain, told NBC News.
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But Kyle has been hiking since he was 3 years old — he was 8 when he hiked Yosemite's punishing Half Dome — and the Z Trail terrain shouldn't have been a challenge to him, especially since the weather had been recently dry.
Plus, Kyle wasn't planning on completing the entirety of the 12-mile hike, and because it was Labor Day weekend, his father figured "there were hundreds of people out hiking, camping in the valley and walking around, so he's not going to be isolated."
So Steve told his son "do a short hike, and it should be OK." But Kyle never returned.
He had brought water, power bars and his cellphone, but "wasn't prepared to be a week in the wilderness."
Police issued a missing person alert for Kyle on Aug. 31, and by Sunday about 50 volunteers and half a dozen professional rescuers were involved in the search.
Steve Brittain said the team who helped to find Amanda Eller, who spent more than two weeks lost in Maui's Makawao Forest Reserve, are on the ground on the Big Island looking for Kyle.
"Trying to sleep, knowing that he's out there, is killing me," Brittain said Sunday. "I was up at 3:30 this morning looking at the stars, praying that we can find him today."
Elisha Fieldstadt is a breaking news reporter for NBC News.