Lou Whittaker, 95, renowned mountaineer

Lou Whittaker, an elder statesman of American climbing who led pioneering expeditions to Mount Everest, started one of the country’s premier guide services and summited his own backyard peak, Mount Rainier, more than 250 times, died March 24 at his home in Ashford, Wash. He was 95.

He had congestive heart failure, said his son Peter Whittaker.

With his twin brother, Jim, Whittaker formed what the BBC once described as the “First Family of American mountaineering.” The siblings began climbing at age 12, discovering that the mountains near their Seattle home offered a refuge from the pollen and pollutants that triggered their asthma, and went on to tackle some of the world’s highest peaks, ascending mountains in Alaska, the Himalayas and the Karakoram range.

“Mountains were the source of his health, the wellspring of his confidence, and the stage for his triumphs, and he was one of the first to make mountaineering and its benefits accessible to the broader public,” the mountaineering company RMI Expeditions said in a tribute. Founded in 1969 by Whittaker and his business partner Jerry Lynch, the guide service — also known as Rainier Mountaineering Inc. — leads expeditions around the world and has helped some 80,000 climbers ascend Rainier, the highest mountain in Washington.

While his brother Jim Whittaker became known as the first American to summit Everest, Lou Whittaker remained most closely associated with Rainier, the 14,410-foot capstone of the Cascade Range. He summited the mountain for the first time at 16 and acquired the nickname “Rainier Lou” while helping others navigate its glacier-covered slopes, training generations of guides while dispensing advice on everything from the basics of ropes and crampons to the vagaries of alpine weather and terrain.

“Some days you eat the mountain,” he would say; “some days the mountain eats you.”

Whittaker survived at least three avalanches, including while climbing Rainier with his son Peter in 1978, when he was swept nearly 500 feet down the slope and narrowly avoided falling into a crevasse. During an Everest expedition in 1984, he was approaching a camp at 25,000 feet, lashed by cold wind that penetrated his sunglasses and goggles, when his vision deteriorated and he realized his eyeballs had frozen. He spent a night in his tent, experiencing what he later called the worst pain of his life, before bandaging his eyes, blindly rappelling down the slope and reaching a lower camp, where he slowly regained his sight after a week spent in near-total darkness.

“There’s a certain amount of risk involved in life,” he later said. “When it comes down to dying, I want to know what it is like to have really lived.”

Early in his mountaineering career, Whittaker was virtually inseparable from his twin brother. The two men trained together, climbed together and were almost indistinguishable, although Whittaker was right-handed (Jim is a lefty) and was the more gregarious of the two. Reporting on the lead-up to an unsuccessful 1975 expedition to K2, the world’s second-highest mountain, Sports Illustrated noted that in contrast to the “soft-spoken” and “slightly wistful” Jim, Whittaker was “all winks and guffaws,” dressing “gaudily in bell-bottoms and striped turtlenecks” when he wasn’t decked out in climbing gear.

Both men were selected for the historic 1963 American expedition to Everest, led by Norman Dyhrenfurth, and trained together in the Pacific Northwest, preparing for high-altitude conditions on the world’s tallest mountain by seeing who could hold their breath the longest while commuting to their day jobs in Seattle.

Mr. Whittaker continued climbing into his late 70s, completing his last major expedition at age 60, in 1989, when he returned to the Himalayas.