Yes, I know stupid question. It just interests me how it is. I imagine it so scary and sometimes I think about that while hiking up. Riding with peeper, shovel and that other thing (don't know its name in english) is necessary and I will invest in an ABS as soon as possible, but this just gets me every time.
I think those videos are good examples (one is not ski related, but whatever) what can happen, although it is unlikely.
"The crickets and the rust-beetles scuttled among the nettles of the sage thicket. "Vámonos, amigos," he whispered, and threw the busted leather flintcraw over the loose weave of the saddlecock. And they rode on in the friscalating dusklight."- Eli Cash
Your chances in a small storm cycle soft slab are decent as long as there is no terrain trap and you don't get slammed into a tree or pulled off a cliff (which is fairly common since cliff bands increase the likelihood of release). That being said we just had two people die this weekend in Teton County due to soft slab failure at only 8 inches. Both were killed by trauma from collision and not burial (SIP).
If you manage to propagate a deep layer hard slab then you might as well kiss your ass goodbye. Where as a soft slab will often release at the first point of contact, a hard slab is more likely to trigger once your well exposed on the layer. An ABS pack might help keep you on top, but just the forces of the snow in a large slide potentially could kill you.
Sooo... when you say the proper equipment gives you a "pretty good chance of survival" that's assuming you don't die before before the snow comes to a stop. If you do, and your now frozen 3 meters down in snow as hard as concrete, hopefully your partners are competent enough to find and dig you out in 10-15 minutes.
My point being that faith in equipment is faith misplaced. Strong terrain evaluation, local snowpack knowledge, and proper decision making, is more likely to save your ass by keeping you out of the slide in the first place.
Yes, I have and it's a horrendous experience. I was about 12 years old (i'm now 25) I still get nightmares and jumpy in the mountains as a result of rumbling sounds. Honestly I don't really freeride in risk zones any more, I did for years afterwards but in the last 4 or so years i've gradually given up and moved in to the park. One of the few guys that started riding pow and gradually gave it up for park skiing i guess. Maybe one day I'll move back.
"Lucky to survive 3 hour"?! where the hell did they get that number. A avalung may give you to 45 minutes tops if your crazy calm and not too compacted. No way that dood survived 3 hours under '60' feet of snow.