Climbers descended into the hole and spotted the snowmobile driven by Shjon Brown of Fairbanks.
The Fairbanks Daily News-Miner reported that the boy was with his father Saturday riding in the Hoodoo Mountains off the Richardson Highway between Delta Junction and Glennallen.
They were about five miles northwest of the Arctic Man Classic, a race involving snowmobiles and skiers or snowboarders.
The boy was riding with his father and others at about 3:30 p.m. and his father took a break to watch from a hillside.
He told troopers that Shjon, pronounced Shawn, rode around a small mound and did not reappear. His father went to investigate and saw the crevasse.
The hole was reported as a "moulin," a hole formed when water of the glacier surface erodes the ice.
The boy was wearing a helmet and goggles.
Climbers from North American Outdoor Institute and an emergency room doctor reached the bottom of the crevasse.
A climber spotted the boy's goggles and helmet and the partially visible snowmobile.
Trooper spokeswoman Megan Peters said investigators believe the boy is under the machine in deep snow.
Personnel from the Army's Black Rapids high angle rescue team also responded.
Authorities were deciding Sunday whether to attempt a recovery.
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Information from: Fairbanks (Alaska) Daily News-Miner
