"This is a great loss for my family right now," the boy's father, Kevin Bardsley, told reporters.
Garrett Bardsley was last seen Friday morning, when his father sent him back to camp after the boy got his shoes and pants wet while fishing in a pond near a lake. The campsite has been described variously as 150 yards to a quarter mile from the lake on a well-established path.
Dozens of searchers have spent the last three days searching for Garrett, who was wearing sweat pants, a T-shirt and a black hooded sweat shirt and tennis shoes. He had no food or backpack.
The search has been hampered by cold, wet weather. Rain mixed with snow fell on searchers Monday, and the temperature plunged to 18 degrees overnight. On Tuesday, the high hovered around 50 degrees, said Sheriff Dave Edmunds.
The official search likely will tail off by the end of the week, Edmunds said, "but we're never going to stop looking."
The camp is located in the Uinta Mountains, east of Salt Lake City.
Last September, Carole Wetherton, 58, and her daughter, Kimberly Beverly, 39, vanished in the same general area when the weather turned bad. Fragments of their remains were not found until June.
It was a happier outcome last month, when another Boy Scout, a 13-year-old, got separated from his troop during a backpacking trip and spent two days hiking alone before rescuers found him.