A long-awaited reunion of three college friends turned tragic when a massive avalanche killed two of them during a backcountry skiing trip in the Colorado mountains, family members said.

Alexis Michel Dodin, of Buenos Aires, Argentina, and Simon Martin Ozanne of Maplewood, New Jersey, were killed Tuesday afternoon when the category-5 avalanche — the most dangerous kind — crashed down on them about five miles (eight kilometers) southeast of Aspen, authorities said Wednesday. The Pitkin County coroner said both men suffocated after being buried by snow.

Their friend Jason Luck, 33, from the Denver suburb of Aurora, survived and called for help.

All three had attended the Colorado School of Mines outside Denver. For Ozanne, 35, the trip was a Christmas gift from his wife Jennifer, who is pregnant with their first child.

"We're having a baby, and this was his chance to get out there for one more time. He loved the mountains, he loved being out there," Jennifer Ozanne told The Associated Press. "I gave him this trip for Christmas .... He was doing something he loved."

Dodin, 32, was a French citizen and a resident of Buenos Aires who carried a Houston driver's license, Pitkin County sheriff's patrol director Jeff Lumsden said.

Jennifer Ozanne said her husband grew up in England and came to the U.S. to attend the School of Mines, graduating in 1999 with a master's degree in engineering. He moved to New York and worked as a partner in the international management consulting firm Marakon Associates.

Lumsden said the avalanche was about 200 yards (183 meters) wide and broke away at about 11,500 feet (3,505 meters) above sea level in the White River National Forest. He said it was probably naturally occurring.

"I think they didn't even trigger this thing," Lumsden said. "I think they were just standing there and the whole thing just came down."

The three had planned to ski to the top of a mountain and back down, but by mid-afternoon the snowpack had become extremely unstable, Lumsden said.

The Colorado Avalanche Information Center said five people have been killed by avalanches in the state this season, compared with four in 2005-06. The average is six per season, the center said.

The center said avalanches kill about 28 people a year nationwide.