"The top caved in on them," said Lieutenant Tiffany Peterson, a spokeswoman for the office. Two of the other snowboarders were hit by debris, but they escaped without injury.
The men tried to free Backowski, but the snow and ice was too densely packed, the sheriff's office said.
Rescuers who arrived soon after were unable to find him. They ended their efforts several hours later at around 11 p.m.
A 12-member search and rescue team headed back to the site, about 8,000 feet (2,400 meters) up the mountain, around dawn on Sunday, Peterson said.
They removed a "couple of tons" of ice and snow using chain saws and shovels before finding Backowski's body 8 to 10 feet (2.5 to 3 metres) below the surface shortly before 9 a.m., she said.
The sheriff's office had earlier said Backowski, a resident of Pine, Colorado, was unlikely to have survived the sheer weight of the debris that collapsed on him. His body was taken to a funeral home in the city of Hood River.
Mount Hood was otherwise open to summer skiers and snowboarders on Sunday.
(Reporting by Jonathan Allen; Editing by Cynthia Johnston and Eric Beech)
