It is an interesting question, and one that I have been asked more frequently by both clients and fellow guides. At first it was pretty simple. Do BCA Float Packs or any other air pack really work? The simple answer is yes. You are a large object with the pack inflated, and will come to the surface if you are caught in a slide. Think of a jar of mixed nuts. If you shake the jar, the large nuts come to the surface.
So what are the downsides to Float packs? They are expensive compared to non-inflatable packs (think the price of nice skis, especially if you have to purchase the air canister) and tend to be heavier than non-inflatable packs. The BCA Float 32 with a full canister weighs in at 6.6 pounds or 2984 grams, while a BCA Stash 30 pack weighs in at 2.9 pounds or 1320 grams. Half the weight. Do these downsides outweigh the value of your life? I sincerely hope not.
So why would you not use a Float pack? Some may have heard that they do not work to keep you safe if you are in trees, or if the slide can take you into a bergschrund. What I have to say to this is I would rather be on top of the avalanche going into the trees or bergschrund than inside the dark avalanche traveling into the same objects. I may even be able to (at least in my mind) try and avoid the trees or bergschrund because I can see them. In my opinion it is always better to be on top of an avalanche than inside one.
Should you always use a Float pack? Like everything in this world there is never an absolute. If you are skiing something and the danger is falling to the bottom, not an avalanche, than perhaps adding the weight of a Float pack will be more dangerous. In spring conditions, when there is danger of a wet slide, but not being buried in a deep avalanche you may consider leaving your Float pack at home. However, if I am in an intercontinental, deep snowpack, where there is avalanche danger I am in favor of wearing the Float pack.
Remember to practice using the pack by deploying it once a year. This will help ensure the system works and that you refill your canister once a year. The Float packs come with a three year warranty and can be reused after being inflated. If you are traveling with a Float pack, remember to have the trigger out when you are in avalanche terrain. I have reminded more than one person that we can be exposed to avalanches on the way up as well as the way down.
I hope to see or at least hear about everyone enjoying the backcountry and remember to use technology to your advantage. It is always better to come home to friends and family than not. Be safe and get after it.
Please let me know if you have any comments or questions and I will be happy to respond.