According to Le Dauphine, the paragliding accident occurred at about 11:45am. After take off from Planpraz (2000m), the pilot headed west and into the Brévent couloir.
The Chamonix PGHM initial investigation, includes a witness statement that indicates the pilot took off from the normal south facing launch at Plan Praz and flew west into the Brévent couloir. The paraglider appeared to be caught in sinking air, but continued to fly close to the relief. Particularly strong sinking air collapsed the paraglider wing. The paraglider pilot plummeted 50 meters to the ground.
Lieutenant Colonel Stéphane Bozon, commander of PGHM in Chamonix explained that, "The pilot was flying too close to the ground in turbulent air. "The wing closed asymmetrically before hitting the ground, probably due to the violence of these thermals," he added.
According to Le Figaro, the Chamonix PGHM was alerted by another paraglider pilot, who witnessed this tragic accident.
The rescue team, composed of two PGHM gendarmes and a SMUR doctor, arrived quickly on scene, by helicopter, at 1,850 meters altitude. They declared the man dead at the scene.
At midday, in high summer, the thermals at Plan Praz are particularly strong, with thermic air rising at over 10 meters per second, but also sinking, cool air, will descend at a similar speed. This creates particularly exciting but dangerous flying conditions. A paraglider wing requires ram air to keep its shape and provide lift. Rising thermals allow for rapid height gain but rapidly sinking air will cause rapid decent and turbulent air might collapse the wing.
If a collapse is total, the pilot goes almost into freefall, where part of the wing remains flying, the pilot will fall very fast but there is an opportunity to re-inflate the wing and resume safe flight. If the pilot is flying close to the ground that window of opportunity becomes very small.
A paraglider pilot in free fall might throw a reserve chute, and if there is sufficient altitude for the chute to deploy, the pilot may land safely.
According to Le Dauphine, the Spanish man, born in Santander, was a resident of Chamonix, where he lived with his girlfriend.