Avalanche. It's a word that strikes fear in the hearts of big mountain skiers the world over. And well it should. Those who've lived through it describe being swallowed by the mountain, buried in the cold and the darkness, slowly suffocating. You can't imagine anything more terrifying. Yet every one of the survivors Liz Hayes met has gone back for more. There's something about hurtling through terrain that no one has skied before that trumps any thought of self-preservation. It's all about adrenalin and pushing the envelope. And for that, these powder hounds are prepared to risk everything.