Very high falls have to be done by the power of suggestion. Use multiple shots of one falling to suggest them falling a long time, then cut to them hitting the ground. (They only have to hit the ground from 2 feet up.) If you sprinkle Fuller's Earth on the ground, when the actor hits it will make a nice fog of dust. This is what they did in Evil Dead II, when Ash falls out of the time portal and onto the ground. He was in fact jumping off a 6 foot ladder onto a pad loaded with Fuller's Earth. This effect is also used in "The Wild Bunch." When a man falls off a roof, look closely and you CAN SEE HIM HIT THE GROUND. They dug a hole for the pad and put Fuller's Earth on it.
