Not a lot of information, but I guess it's pretty clear what happened, in broad strokes: Dean Potter Killed in BASE-Jumping Accident
Yosemite Search and Rescue (YOSAR) initiated a hasty search, but the rangers were unable to locate the pair overnight. Potter and Hunt had been attempting to fly along terrain that required them to clear a notch in a rocky ridgeline. “It’s kind of a trickier flight to go through this notch,” Gauthier says. On Sunday morning, a state police helicopter was able to spot both bodies from the air. No parachutes had been deployed. Two rangers were then airlifted to the site to perform the recovery.
It would appear that Clif Bar was accurate in their assessment of his activities.
There's more, if you don't already know who Dean Potter is, everywhere. The National Geographic Adventurer's Blog has this: Pioneering Climber Dean Potter Killed in Wingsuit BASE Jumping Accident
An observer shooting photos of Hunt and Potter’s flight reported hearing two disconcerting, loud sounds in succession that suggested impact—but also could have been parachute deployment.
What a shame.