SANTIAGO, Chile - Douglas Tompkins, 72, cofounder of the North Face and Esprit clothing companies, who bought up large swaths of land in South America's Patagonia region to keep them pristine, has died from severe hypothermia in a kayaking accident in Chile.

The businessman and lifelong outdoorsman was boating with five others Tuesday when their kayaks capsized in a lake in near-freezing waters in the Patagonia region of southern Chile. Mr. Tompkins died at a hospital in Coyhaique, a town 1,000 miles south of Santiago.

Chile's army said strong waves on General Carrerra Lake caused the kayaks to capsize. A military patrol boat rescued three of the boaters and a helicopter lifted out the other three. None of the five with Mr. Tompkins was seriously hurt.

"Doug was a passionate advocate for the environment," the North Face said in a statement. "His legacy of conservation will help ensure that there are outdoor spaces to be explored for generations to come."

The Ohio-born Mr. Tompkins began rock climbing before his teen years, after his family moved to New York's Hudson Valley. He later became an active skier and kayaker.

Deciding against college, he spent a couple of years working, rock climbing, and ski racing in Colorado, Europe, and South America.

In the mid-1960s, he became one of the founders of the North Face, a small ski and backpacking retail operation in San Francisco under the mantra "Never Stop Exploring."

The brand has become ubiquitous in the United States, as likely to be seen on New York subways as on Colorado ski slopes. He founded the Esprit clothing company with his first wife, Susie Tompkins Buell.

After retiring in 1989, he was active in conservation and environmentalism. Mr. Tompkins, who had lived in Chile since 1990, used much of his fortune to buy hundreds of thousands of acres in Patagonia, a sparsely populated region of untamed rivers and other natural beauty that straddles southern Chile and Argentina.

In one of his final interviews, Mr. Tompkins, who is survived by wife Kris and two daughters, was asked how he would like to be remembered. "By this," he said, referring to the preserved lands around him, in an interview with Chile's Paula magazine, published last month.

"I prefer it to a statue. People are going to walk over these lands. Don't you think it's nicer than a grave?"