well, using simple physics, i've determined that mr dumont would have had to fall around 95 feet (or there abouts) to hit the ground at the same speed mr hall did (53mph). so basically, if the height of that fall was more than 100ft, he definately hit the ground at a higher speed
and ,
what makes his crash so much worse was the force at which he hit the ground. in mr halls case, he was travelling forward and had his feet knocked out from under him, so only his feet took the full impact of the blow, whereas mr dumont's entire body smashed into the ground at whatever speed.