Black Diamond Avalung Ski and Snowboard Packs
Read this first. The AvaLung line is discontinued, and in January 2011 the US Consumer Product Safety Commission recalled roughly 3,500 AvaLung packs from the 2010 production run: the air intake tubing could crack in cold temperatures, causing the unit not to work and posing a suffocation hazard. The recalled models were the Anarchist, Agent, Bandit, Covert, Outlaw and Revelation. Any AvaLung on the second-hand market now is more than a decade old, which matters for a device whose failure mode was cracking plastic.
What it was. A mouthpiece and tube that moved your exhaled CO2 to the back of the pack, away from the air you were drawing in, extending the time you could breathe while buried. The physics were sound and it genuinely did what it claimed in tests. It also required you to have the mouthpiece in your mouth at the moment of the slide, which is the practical problem nobody solved.
What replaced it. Avalanche airbag packs, which inflate a balloon to keep you nearer the surface. The battery-and-fan systems have largely displaced compressed-gas canisters because you can fly with them and practise a deployment for free rather than paying for a refill.
And the part this post got right, which has not changed and never will: the device does not replace backcountry knowledge or judgement. A beacon, a shovel, a probe, the practice to use all three inside a few minutes, and companions who can do the same are the safety system. Everything else is a margin on top, and a margin is only worth having once the basics are there. Free avalanche education resources are at avalanche.org.
Part of the guide to ski and snowboard.