They all probably jumped off a spot somewhere near there and were using the ridge lift of those huge hills to climb and stay upI didn't even notice the hang glider spinning down. How do your recover a spin in one of those? How did that thing even get so high up?
For lack of a better term, the hang glider was in a flat spin, most likely due to additional drag or damage on the left wing from the collision. I suspect that neither wing was stalled, but directional control was not possible. In a situation such as this, the chute doesn't help since your vertical speed is pretty low. Best bet is to climb up into the frame as far as you can and hope the downtubes take the impact.I read the hang glider guy deployed his reserve chute, but it tangled on the glider and caused the spinning that we saw. But the result was minor injuries to the hang glider guy as he impacted the trees.