February 22, 2014, Chair Peak Large Avalanche

Some key details that exceed most observations we make:

• 10'crown-skier impact maxes out at 3' down
• Snowpack observations and tests rarely go deeper than 6'
  
  This slab might represent the entire recent storm snow at and above treeline in the Snoq Pass zone where there is no telemetry to look for actual storm totals and winds. This might be similar to the very large slides that came off the Shuksan arm in the 98/99 season which ran multiple times and the MLK crust from that season. The crust posed the risk of large storms lingering until they were 8-15' deep then failed naturally.
  
  

Really appreciate your comments.

I find these deep snow slides are very difficult to predict since many of our typical tools aren't applicable at these scales. The observational tools work, but can't be easily validated with testing. Hopefully the deep weak layer is strengthening. However, the reported slide makes it appear that the large storm slab is very close to naturally sliding, and that is not a comforting thought.

Really appreciate your comments. 

I find these deep snow slides are very difficult to predict since many of our typical tools aren't applicable at these scales.  The observational tools work, but can't be easily validated with testing.  Hopefully the deep weak layer is strengthening.  However, the reported slide makes it appear that the large storm slab is very close to naturally sliding, and that is not a comforting thought.

The weight of one person in comparison to the weight of the snow when the weak layer is buried this far down is insignificant. The inability to trigger slides unless at shallow spots may explain why people in general are observing good stability in their test and observations while out this past weekend, but we are still seeing large failures happen in multiple places. It will be interesting to see what happens as we get a period of warming over the next few days.

Was there an avalanche at Chair on 2/22 and 2/23?

Sorry. Typo on my part. Fixed in the original post.

I think we can all accept that people are gonna do stupid things, but if you belong to this site, and buy gear from this site, and post avalanche incident notifications, then I think you can expect that the tribe will want to have its say. And is that such a bad thing? There are a lot of people here who know a lot of stuff.

Over the past few days, I've participated in a review of an accident ( with fatality ) that occurred last year. It didn't happen on Chair Peak, and it was skier-triggered rather than remotely-triggered, but other than that, the incidents are pretty much interchangeable. Increasingly that's what I see when I review accidents. The names of the people and places are different, but pretty much everything else is the same.

This was an interesting TR, on the same day as this chair peak slide:

www.turns-all-year.com/skiing_snowboardi...ex.php?topic=30882.0

The aspect is different, but it's the same big dump of snow on the same three weeks of crust.

This was an interesting TR, on the same day as this chair peak slide:

www.turns-all-year.com/skiing_snowboardi...ex.php?topic=30882.0

The aspect is different, but it's the same big dump of snow on the same three weeks of crust.

I probably wouldn't have pushed my luck in the slot on that day (nor would most people I ski with), but I wasn't there, so I can't say if it was safe or not. It may have been a perfectly reasonable call, who knows...not I.

Though I will offer this: plenty of the time survival is blind luck. This was illustrated to me a couple of years back when I was returning to the Baker ski area, back from Ptarmigan Ridge and Table Mountain. The avalanche risk was what I would consider quite serious. I had been out there a couple nights and it snowed more than expected, so I managed things best I could, and kept it as mellow as I was able. One slope I had to ski cut and it slid rather significantly. Upon nearing the ski area I saw plenty of "sick line, bro" folks dropping off the ridges (some corniced, plenty loaded) right outside the ski area, where it is not controlled. All it takes is one guy doing it, and all the other sheeple follow. Anyway, it wasn't a smart day to be doing that given the conditions. I don't think anybody who had a clue about avalanche risk would have been, but it's safe to say 99.99% of the folks doing it didn't fall in that category. Luckily they didn't trigger anything, but they may well have. Let's say the risk was 10% to trigger something; and yes, I realize this isn't something you could ever put a statistical chance on, but I digress. I imagine most anybody here would say that is far too high of a risk to take. On the other hand, if 9 people drop in on one of those lines, it's also perfectly possible that nothing will trigger. When nothing does, it simply reinforces the behavior. Maybe those folks I saw that day will have their luck run out at some point, or maybe they won't, who knows. What I took from that experience was that I never want to operate that way, and I'd prefer to stack the deck in my favor. Will that remove all risk, or guarantee that I won't screw up at some point? Of course not, but I'm at least going to try my best.