A 40-year-old American mountain climber hailed as the best of his generation was given up for dead today after he and a companion disappeared in an avalanche in the Himalayas Tuesday.

Alex Lowe and climbing companion Dave Bridges were swept away by a massive slab of ice and snow that hurtled down the mountain at 100 mph during an expedition to ski down one of the world's highest peaks.

Lowe, of Bozeman, Mont., and Bridges, 29, of Aspen, Colo., were presumed dead after the accident on 26,291-foot Shishapangma in Tibet, according to a report from their climbing partners posted on a Seattle-based Web site monitoring the expedition. A third climber, Conrad Anker, escaped with a broken rib, torn shoulder muscle and head lacerations.

"After 20 hours of searching through one to 20 feet of debris, we've given up on Alex and Dave as dead," team member Andrew McLean said in a dispatch posted on MountainZone.com.

Lowe was considered perhaps the world's strongest climber, having reached the top of some of the most forbidding mountains, but it was his style that caused Outside magazine to call him the world's best climber in a March profile. "He understood it's not just about the yardstick of distances and heights," said Hal Espen, the magazine's editor, "but about climbing in ways that are both spiritually and aesthetically beautiful."

Lowe made a record conquest of seven peaks in less than nine hours in the Grand Tetons of Wyoming, ascended Great Trango Tower in Pakistan via the previously unconquered northwest face, reached the summit of Mount Everest twice and was a pioneer in Antarctic climbing, making first ascents on at least five of the frozen continent's peaks.

Lowe himself shrugged off the greatest-climber label. "There might be a fastest runner or a highest jumper," he said in an interview with MountainZone. "But climbing is different. It's just too subjective. And it's a lifestyle; it's not a sport."

CAPTION: Renowned mountain climber Alex Lowe, shown in this 1996 photo, and a companion were reported to have died on a Himalayan peak.