Two well-known BASE jumpers, Dean Potter and Graham Hunt, died Saturday while attempting a wingsuit flight in Yosemite National Park, a park spokesman has said.

The pair had jumped from a 7,500 foot promontory called Taft Point, but the parachutes designed to slow their descent had not been deployed, according to park ranger Scott Gediman.

Someone called for help late Saturday after losing contact with Potter and Hunt, and their bodies were spotted in Yosemite Valley by a helicopter crew Sunday morning.

Potter and Hunt, who both lived near Yosemite, were prominent figures in the park's climbing community, according to Gediman. "This is a horrible incident, and our deepest sympathies go out to their friends and family," he said. "This is a huge loss for all of us."

BASE jumping stands for "buildings, antennas, spans (such as bridges) and Earth (such as cliffs and mountaintops) that jumpers can parachute from. It's illegal in all U.S. national parks, and it was possible the men jumped at dusk or at night to avoid being caught by park rangers.

Potter made a name for himself in recent years with a series of daring and often controversial stunts.

Last May, he jumped from a 13,000-foot mountain peak called The Eiger in Switzerland with his dog on his back.

He's also climbed some of the world's most daunting big walls and cliffs alone, using his bare hands and without ropes. He took the sport to an extreme level with highlining — walking across a rope suspended between towering rock formations while wearing a parachute for safety in the event of a fall.

He drew criticism in May 2006 after he made a "free solo" climb of Utah's iconic Delicate Arch in Arches National Park. Though the climb was not illegal, outdoor clothing company Patagonia dropped its sponsorship of him, saying his actions "compromised access to wild places and generated an inordinate amount of negativity in the climbing community and beyond."

Potter defended his ascent, saying his intention was to inspire people to "get out of their cars and experience the wild with all their senses."

Last year, Clif Bar withdrew its sponsorship of Potter and four other top climbers, saying they took risks that made the company too uncomfortable to continue financial support.

In 2009, he set a record for completing the longest BASE jump from the Eiger North Face in Switzerland by staying in flight in a wingsuit for 2 minutes and 50 seconds. The feat earned him the Adventurer of the Year title by National Geographic magazine.

A photographer who documented that jump, and has known Potter for more than 15 years said Potter stood out from other climbers not only for his skills but his boldness.

"BASE jumping is the most dangerous thing you can do. The odds are not in your favor, and sadly Dean pulled the unlucky card, " Corey Rich said.

Potter indicated in his writings that he knew the inherent danger of his sport. Last year, his friend and climbing partner Sean "Stanley" Leary died during a BASE jump in a wingsuit in Zion National Park in Utah. Potter was among a group of people who recovered Leary's body.

"Though sometimes I have felt like I'm above it all and away from any harm, I want people to realize how powerful climbing, extreme sports or any other death-consequence pursuits are," he wrote in an October 2014 blog posted on his website. "There is nothing fake about it whether you see it in real life, on YouTube or in a glamorous commercial."

Potter also said he was studying aerodynamics and aerospace technology, and was determined to develop safer gear and methods of flying.

Gediman estimates that about five BASE jumping deaths have occurred in Yosemite. He said he himself watched a BASE jumper leap to her death in 1999 when her borrowed chute failed to open.

The woman was participating in a protest against the National Park Service's ban on BASE jumping.

Additional reporting by Mashable

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