Sheriff Marty Gleave said his deputies and Utah State Parks rangers rushed to the reservoir's Fisherman Beach area at 4 p.m. on a 911 call that two people had gone overboard. Neither reportedly was wearing a life jacket.
"The victim [had] jumped into the water to save his 12-year-old son, who had jumped in after a hat that had blown into the water," the sheriff stated. "He was able to get his son back to the boat but was unable to make it himself."
Waters of such high-elevation lakes in Utah are typically very cold this time of year, increasing the potential of debilitating muscle cramps for swimmers.
Otter Creek State Park Manager Bob Hanover said Gunter, his wife and their four children were in an aluminum fishing boat.
The family had been camping with the parents of Gunter's wife's on land owned by the Bureau of Land Management, Hanover said.
After Gunter went under, the others in the boat alerted people on shore, who ran to a park ranger's residence a few miles away. At the same time, others on shore dialed 911 from a nearby marina. The ranger was alerted about 4 p.m. and used his boat to begin the search for Gunter.
Over the next four hours, search and rescue personnel from Piute and neighboring Sevier, Sanpete and Washington counties looked for Gunter.
His death stunned people who knew him.
Bill Okeson said Gunter was his next-door neighbor for about 10 years. News of the tragedy, delivered by the bishop of their local congregation of The Church of Jesus Christ of Latter-day Saints, about knocked him off of his feet, Okeson said, and is still hard to process.
"I wouldn't feel like that if I didn't care about him," Okeson said. "He's just way too young for this to happen."
Gunter had three sons and a daughter, according to Okeson. The 12-year-old son is the oldest child, and his youngest, also a boy, just started kindergarten last fall.
Okeson said Gunter owned two trucks that he used to transport materials to the booming oil fields in North Dakota. The work required him to be away from his family for weeks at a time, but when he was home, he could usually be seen playing in the yard with his kids, Okeson said.
Gunter also lived for the outdoors and would take his family on outings at least five or six times a year, his neighbor said.
"He hunted and fished all the time," Okeson said. "The outdoors were a big part of his life."
Okeson said his wife has visited Gunter's wife and their children several times since the accident. He said the family is "just devastated."
Leha Gunter, reached Thursday at the family home, thanked well-wishers for their interest but did not want to talk about her husband. She asked that her family's privacy be respected.