The major concern with paying out slack is the possibility of a carthweel type fall. (a good posibility on steep terrain) In this case, slack could very easily wrap itself around the neck of the skier, or around an arm, etc, etc. Falling with the rope wrapped around any part of your body is not pretty, think arms being completely ripped off. (in the event of a long vertical fall, in your case it would probably be much less severe, IE broken limbs and severe rope burns) Also, the elasticity of the rope would drop you off of the cliff if you let out enough for the run. This would leave you stranded halfway down a cliff band, possibly injured, and with no way for the belayer to know what has happened. Also, if you pull out enough slack for the entire run, a fall could result in the rope being pulled laterally as it is coming taunt, possibly resulting in it being severed by a rock. If you don't pull out enough rope for the whole run, you still have the same problem as pulling no slack at all. Personally, I think a slack rope would be more dangerous than no rope.[/quote]
All good points. I have several friends who have jumped off cliffs on 50 m ropes and come away fine, so I know it can be done. One did it for a James Bond movie,another to promote his custom climbing harnesses. I was saying coil the rope up top to keep from getting wrapped in it. Someone might be able to feed it with a loose body belay if they have a good jacket and gloves to keep from beeing burned.
I have seen lead climbers wrap in the rope on the way down and unwrap like yo yo. They all had rope below them to wrap in, but the cartwheel scenario is possible.
I'd use two 8 mil ropes designed to be used as twin ropes for safety. They have the lower impact force than two regular ropes.Check the Mammut catalogue for a good explanation.
The impact force at full length is far far below what it takes to remove a limb. It would kill you if it wrapped around your neck for sure, but the "catch" feels like falling into a bunch of pillows, sort of like a bungy without the rebound.
Anyway, I'd like the rope to be something to save your life if you screw up. If you think you'll probably fall skiing don't do it---just abseil it.