Only the family's 4-month-old yellow Labrador retriever survived the hike. He was found near Decareaux, who died at the scene, and the two boys, who were declared dead at a hospital after hours of efforts to revive them failed.
The tragedy crushed Decareaux's father-in-law, Keith Hartrum, who described the family as tightly knit, "always on the go and adventurous."
"Dave was a great guy, a good father, son-in-law and husband," Hartrum told The Associated Press. "Those two boys were just precious — smart, very nice kids."
It was nearly 60 degrees Saturday morning when Decareaux and his sons set out on the popular trail that runs through a sparsely populated area of southeast Missouri. Decareaux was wearing only a light jacket, while one of his sons was clad in a fleece pullover, and the other a sweater, Volner said.
They were ill-equipped as the temperature sank into the 40s, and a storm that would drop 2 inches of rain set in, making the trail all but impassable.
Volner said there are no caves or other places of refuge along the trail. Although Decareaux had a cellphone and flashlight with him, both devices lost power at some point, his wife, Sarah, told the St. Louis Post-Dispatch on Monday.
A passer-by spotted the hikers more than three hours into their journey and asked if they needed a ride back to the Brushy Creek Lodge near Black, where Decareaux's wife and their three other children — ages 12, 4 and 2 — were staying. But Decareaux declined, telling the man they could make it back, the sheriff said.