Remotely triggered avalanche catches, carries and buries two skiers ascending the up-track on
the westerly aspects of Pete’s North ridge near treeline. One partially buried and one fully buried. Both ok.
Type: Wind slab
This was a 1finger hard wind slab sitting on a thin layer (2″ and less) of 4finger hard low density powder over harder (pencil hardness) wind slab that acted as the bed surface.
Size estimate: 150′ wide x 5-700′ x 12-18″ deep
Trigger: Skier remote from ~20-30′ left from corner of the right flank and stauchwall. (see photo)
Weak Layer: broken precipitation particles/decomposing fragments
Debris: ~3-5′ deep (fanned out to some degree)
The avalanche was remotely triggered by a skier from a safe, flat, ridged section of the slope just above treeline. That person felt a “collapse” which propagated to a higher elevation adjacent 37-40+ degree slope and the avalanche resulted. Five skiers were stopped at this safe area and two were still hiking up in lower angle terrain below.
The debris overran a shallow depression and was deposited on a sub-ridge/bench terrain feature with sparse trees. The two skiers still hiking were in this lower angled terrain when the debris caught them. They were believed to have been carried 150-200′ with one skier partially buried and one fully buried. The latter was buried under just inches to, at most, 1 foot of snow and wedged against a small tree. The five remaining skiers mounted an excellent quick and efficient rescue. Beacons were used to locate the skier fully buried when one person noticed a hand. At this point, they were able to clear the airway and the skier was able to breath on their own. It was estimated to take as little as 3 minutes, but possibly more, from the time of the avalanche to clearing the airway. The skier partially buried was able to dig most of himself out and help with the rescue of his partner. Both buried skiers were able to ski out on their own power.
The debris from this avalanche nicked one small 50′ section in the zig-zag of the ‘relatively’ safe up-track (where skiers were caught). A small section of the up-track was also covered with a very small amount (1′ or less) of debris near the toe.
This was a close call that we all can take something away from – some lessons learned:
1- Keep your rescue skills honed – KUDOS to these skiers for their excellent quick response!!!
2- Never underestimate where and what terrain features an avalanche can overrun.
3- When visibility does not let you see the whole picture clearly, placing a skin track even more conservative than you may think necessary is not a bad idea and could save a life.
4- Always keep your beacon batteries fresh.