The avalanche happened Friday afternoon on the west face of Mount Jumbo, The Missoulian reported Sunday.
The snow destroyed the home of Fred Allendorf and Michel Colville at the base of the mountain, burying them and Scoles-Coburn, 8.
After several hours of digging by rescuers and neighbors, the three were pulled from the snow and were taken to a local hospital where they remained Saturday.
West Central Montana Avalanche Center Director Steve Karkanen said a snowboarder was the likely cause of the avalanche.
"All it was waiting for was a trigger, and we got that with the snowboarder," Karkanen said. "He was on a slab probably 2 or 3 feet deep. It collapsed with a whoomp and he started to go for a ride. He got caught in it for a while, but got free."
Authorities said avalanches still pose a threat to Missoula homes along Mount Jumbo and Mount Sentinel.
"Many people reported to us on Friday that they triggered wind slabs and experienced collapse and fracture propagation in areas loaded by the wind on Mount Sentinel," Karkanen said. "It's been many years since Missoula has seen a full-on blizzard with this much snow. High winds are expected again ... and will continue to load these low-elevation slopes. Please respect these conditions and avoid Mount Jumbo and the steeper slopes of Mount Sentinel for a few days."