Base jumpers -- How much impact force is survivable?

[AlexPski]

So I've been becoming pretty obsessed with base jumpers. However its a pretty dangerous sport and as it turns out (surprise) a lot of them die. I was just wondering how much force the human body can survive. Say a 90kg base jumper jumped off of a 900m mountain and their parachute failed to open or had a malfunction, obviously they would not survive but how much force do they actually experience when they hit the ground? And what is survivable by humans?

 

[russ_watters]

Welcome to PF!

Impact force isn't really a useful thing because you can impart a very high force for a very short time and not do much damage. In addition, the injury caused by impact with the ground varies greatly with how you hit the ground. In general though, injury is a function mostly of acceleration. 100g is about the limit:
http://en.wikipedia.org/wiki/G-force#Short_duration_shock_and_jerk