Stather, 41, who worked in Calgary as a pulmonary specialist, had done a successful jump with a wing suit Friday morning with two friends.
He told the pair he wanted to do one more jump and hiked back up the cliff. It was during that second jump that he was killed, according to Det. Pat Barr with the Coconino County Sheriff's Office in Arizona.
"The two stayed behind at the bottom to watch for him. After a period of time went by and they did not see him jump, so they decided to hike back to the top. They could not locate him at the top of the rim where their cars were parked."
BASE jumping is similar to sky diving, but a person jumps from a building or cliff, rather than an airplane. BASE stands for building, antenna, span, earth.
Fellow pulmonologist and friend of Stather, Elaine Dumoulin, said the physician was an avid skydiver.
"He was an amazing guy. He was very generous, very intense, he was living his life 200 per cent," said Dumoulin.
"One thing he taught me was actually to live every day as if it was the last one and to enjoy every moment because he said life was short, but we needed to live it intensely, and he was passionate about everything he was doing."
Dumoulin said Stather loved his work and said his patients were very important to him.
Police arrived on the scene late Friday night, and Stather's body was recovered Saturday.
Stather was wearing a wing suit and had jumped from a cliff that was at a 45-degree angle, according to police.
"Between where they would launch from and the canyon floor, there is terrain on the way down, almost as if it's a ridges and a step type terrain," said Barr.
"The idea is to fly over all those ridges to get down to the bottom, and it appears he may have miscalculated the height of one of those ledges and did collide with it."
Barr said the area is remote, and while it is not known for BASE jumping, another man, from Norway, died there doing the activity about a year ago.