How much lateral velocity would be required to clear side obstacles, given the fall distance? The guy is dead.
Lots of variables there. Given that he started 1.5 miles away from the Colorado River in the main canyon (per post #69) and that it would take 27 seconds to fall 4,000 feet (per post #72), that works out to about 200 mph of lateral velocity at the start of the fall. Of course, this does not allow for air resistance slowing his lateral speed, so the initial lateral velocity needed would have to be considerably higher than 200 mph.
I have no doubt that the guy is dead, though.