Dean Potter, 43, died while attempting a wing suit flight from 7,500 ft in Yosemite National Park, where he also lived with his girlfriend and her three children.

His fellow extreme athlete Graham Hunt also died during the incident, with the pair’s bodies later being recovered by rescuers after a search from the air.

The two men were wearing special skin tight suits with batwing sleeves and a flap between their legs to help them ‘glide’ and had been seen taking off from the rock by a witness.

The witness saw them descend into the valley with their wings visible, but then they fell out of sight, and then a 'pop-pop' sound was heard. They had hoped the noise was their parachutes deploying, but it turned out it was not.

‘This is a horrible incident’ said Park Ranger Scott Gediman, ‘Our deepest sympathies go out to their friends and family.’

Extreme sports like this are banned from Yosemite National Park, but due to its sheer size some enthusiasts frequently manage to evade authorities.

Dean Potter was a leading light in both base jumping and ‘extreme highlining’ - where athletes walk across a tightrope between rock formations with only a parachute for safety.

He was an expert rock climber and base jumper, and famously made a 22 minute film called When Dogs Fly, which showed his various activities accompanied by his dog Whisper.

In a recent post from his Instagram page, he wrote of the sport that would later kill him: ‘I don’t fool myself thinking I’m any better than my fallen brothers and sisters but I do stack the odds in my favour and focus everything in my power to #fly conservatively, so I’ll hopefully be around to see this incredible new outdoor art form beyond its infancy.’

Dean leaves behind a partner Jen Rapp, and his beloved dog Whisper who featured frequently in his projects.

Speaking of her partner, Jen said: 'Dean truly loved Yosemite.'

'His heart, spirit and passions soared in the valley; it was his home. The beauty of Yosemite inspired him to be the best possible artist, partner, father and friend. This is exactly where he’d want his rule-breaking, fringe-pushing, counterculture spirit to live forever.'

Fellow climber Doug Robinson said of his death: ‘We’re very sad about Dean Potter’s death, but not very surprised.’

‘He was pushing the envelope all his life.’