Bruce sent this email and video footage of teh Float 30 Airbag in action
As you probably know, one of the biggest trends in avalanche rescue equipment is the increasing use of avalanche airbags. How well do they actually work? Here’s some interesting helmet cam footage of an airbag in use earlier this week in Alaska:
http://www.backcountryaccess.com/blog
The potential victim was wearing a Float 30 airbag from BCA. While it’s difficult to see the airbag itself, note the orange glow when the bag is deployed, just before the sky reappears. You can also see the orange bag toward the end of the footage on the edges of the screen--and in the user’s shadow. This also illustrates how the location of the airbag behind the head and shoulders prevents the loss of peripheral vision and upper body mobility.
Note how the potential victim ends up with his head facing up and his feet pointing downhill; this is the safest position for protection from asphyxiation and trauma, the two most common causes of avalanche fatalities. Most important, of course, he’s on top of the debris instead of beneath it!
We still have samples available of next year’s new models: the Float 18 and Float 36. Please let me know if you’re interested in borrowing one for the remainder of the season.
Looking forward to your reply.
Cheers,
Bruce E.
The group had dug pits and there were no avalanches on similar slope aspects. The guide had already skied the slope. A lesson in spatial variability maybe? The video is in Alaska and the weather was anticyclonic prior to the incident.
Prior to our arrival, there had been a long period of persistent high pressure over Alaska and the Yukon. (In some areas the barometric pressures measured were the highest on record). This lead to a lack of percipitation and high winds through the mountains. This left in most areas a thick layer of windslab as the effective base to the new snow we were skiing on. (Imagine Las Lenas after a long dry spell).
The week before 0.5"-2" inches of new snow had fallen. There had been one clear cold night that week that had lead to some surface hoar development on this thin layer. There had been additional new snow (6"-18", depending on elevation and zone) 2-4 days prior and light winds in most areas. The new snow was ‘right side up’ or uniform for the most part, since the weather had been warmer at the start of the snowfall than at the end and had had a couple of days to consolidate.
As such, the major risks were from a larger area with a hoar frost layer under the new snow, and/or places where the new snow was poorly bonded with the windslab. We hadn’t seen any larger patches of hoar frost higher up in that zone on that aspect or at the top of the run we were on. The run we were on also didn’t have a history for hoar frost developement. We seen some sluffing down to the bed surface but nothing that propogated seriously.
