That wasn't why I was asking. Just curious why no disconnects on a trail like that, they make for much better traction and a comfy ride.

As for why a CV joint blows, it's as simple as applying power to it when it is beyond the limits of its travel.

I don't think Stormy has the diff drop kit from SLR, and if his suspension was at full extension (he was going up a hill I think) it could cause the CV joint to exceed its angle limit and break.

Anyone with a lift can check this out.
Jack the front of the Xterra up so the front wheels are off the ground.
Try turning an axle by hand (hubs unlocked).
Feel it bind.
Add power and it will eventually break.