I've only been in this situation once and it has been a life lesson for me and I'm reminded of it everyday. Especially when I go skiing and have to put my brace on.
Here's what I learned:
1) I shouldn't have been where I was. I didn't have the skill or experience for it. 50deg pitch at Tuckerman's Ravine. Doesn't mean others shouldn't be there; just that I wasn't ready that cruddy spring snow an something that steep.
2) Leki trigger poles can come off in a fall. I lost one and kept one. Had nothing to do with touching the top; they have a sort of binding set up so they will come off if yanked. Wish I read the ski pole technique prior to the trip. It might have worked for me.
3) If you are heading down hill on your back head first, as I was, DON'T LET YOUR SKI TAIL TIPS TOUCH THE GROUND! That's how I lost my ACL, and sprained my MCL. You risk your skis doing a helicopter spin as mine did.
3a) Though my ski tails touched causing a heli spin and tore my acl, this might have also saved my life. When this happened it caused me to slow down, spin around and stop.
3b) If you want to risk using your ski tails, my GUESS would be to turtle up, put both knees together, wrap your arms around them (like in a cannon ball jump into a pool) and pray it works. I would expect this could cause the skis to come off and crack you in the head though. At least your knees will be supported by the other and your arms.
3c) This happend not because I was trying to dig my ski tips in but because I was grabbing for the ground trying to dig my fingers into the snow to slow down, while keeping my head off the ground so I wouldn't break my neck. This caused my ski tails to hit the ground. I was looking uphill so it was like doing a sit up. My focus was on my hands and I wasn't even thinking about my legs.
One thing I do know is that if the brake is down hill from you, you risk doing a rag doll fall. I THINK everything should be done to have the brake up hill.
4) You aren't going to be able to figure out what to do on the way down, so if you are going into steep terrain that has the potential for this, you should train for it so it is a reaction and not try to figure it out as you're sliding at high speed.
4a) You can think about it all you want but until you try it, you won't really get what it takes to stop.
Finally, even though I was hurt when I fell, my injuries were minor compared to what can happen and it was still a GREAT DAY of skiing. I hope to go back in another year or two.