Avalanche discussion thread

[j_b]

I haven't seen an overview of the slide yet. Has anyone seen any info as to how the snowpack likely failed (in the trees apparently?) and a terrain description?

[iain]

I was curious if it released on the widespread surface hoar reported in the Stevens Pass and Methow areas in the days before the storm.

[twz]

It appears that the forecast was High on the upper slopes and Considerable on the lower slopes of Cowboy Mountain

 

NWAC History

[Seamstress]

Haven't seen a good analysis yet. Further south, the Cascades generally had a significant ice layer formed by a rain event at the end of the last big storm cycle, followed by cold. Note the numerous climbing accidents in places where climbers generally unrope and feel safer - Crater Rock on Hood had three accidents in the previous week including a fatality. Actually, I still see two significant ice layers in the snowpacks round here with sow not bonding.

 

Keep checking the NWAC where a report should eventually be posted.

[Dannible]

It appears that the forecast was High on the upper slopes and Considerable on the lower slopes of Cowboy Mountain

 

NWAC History

 

I'm somewhat confident that NWAC reported Considerable for those SW to SE facing slopes and high for N and NW facing slopes at that elevation that day. I may well be wrong but I read and reread that a couple of times afterwards. The lower slopes on that map are moderate. The difference is small and subject to error due to wind transport and a lot of other variables, but there is a difference. Not making excuses for the guys, just trying to get the facts straight.

[kurthicks]

Dan is correct, although NWAC did their usual midday update on Sunday at 3pm (after the accidents) which upgraded the danger rating from Considerable to High on all slopes above 5000'.

 

Here's the forecast you would have had if you checked NWAC on Sunday morning (produced Saturday morning at 11am).

 

http://www.nwac.us/archive/sabsea_2012-02-18-1055.html

[orion_sonya]

I was not up there on Sunday - were there sunbreaks? The forecast mentions increased danger do to sun exposure on the south facing slopes.

[BirdDog]

I was not up there on Sunday - were there sunbreaks? The forecast mentions increased danger do to sun exposure on the south facing slopes.

 

I headed up to Stevens on Sunday with my kids to ski inbounds. We got there about 10AM, and were turned back due to all parking full. On the way up the sun was definitely breaking through the clouds. I don't know what the sun was doing at the time of the slide.

[Seamstress]

Most ironically, the fundraiser for the NWAC - VertFest - was held that weekend at Alpental. It is a travesty that they aren't in operation for a longer part of the ski mountaineering season and operate on such a shoestring budget. People can not abdicate responsibility for their safety, but people are in fact using their reports to help them make decisions.

[tvashtarkatena]

The new NWAC avi map is really kewl.

[dougd]

I think alpine climbing was more fun before the "information age" arrived. Another thread, another time perhaps...

 

My, but the handringers are out of their holes aren't they...

[tvashtarkatena]

That's just because you were younger!

[dougd]

That's just because you were younger!

 

Yeah, no doubt.

 

Now I'm "older", and I do use a lot of the weather and avy information available before trips but it can be a detriment if one let's it overtake common sense, thoughtful planning, and experience to cancel trips where dangers can be managed as they should be with or without all the technology, ad nauseam...

 

Anyway, let the handwringing and gnashing of teeth continue. My apologies for interrupting.

 

d

[tvashtarkatena]

But all that data at your finger tips just helps you point cherry pick the conditions better!

[twz]

Even if the danger was just Considerable, the advice is:

 

"Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential."

 

And the Likelihood of avalanches is:

 

"Natural avalanches possible; human- triggered avalanches likely."

 

Avy Danger Scale

 

Based on this advice I would avoid these slopes.

[Kyle_Flick]

Telemarker and I were out skiing in the backcountry the weekend before on the north side of Mt. Stuart in low to moderate avy conditions as reported in NWAC and still experienced an avalanche. So my advice is before heading out into the backcountry, make sure your Will and life insurance are all in place. S@#t happens, and we aren't yet ready to sit out our days on the couch eating bon bons. You've heard the old adage before: The more you're out there, the greater are your chances of getting caught in an avalanche.

[pcg]

I'm surprised at how many people head for steep bc slopes when avy conditions are considerable, let alone high. If you've taken Avy 1 you've learned that most avy deaths occur in moderate (level 2) conditions. What you can take away from this statistic is that most people stay away from level 3 (considerable) and up and that level 2 is plenty to kill you.

As a first rule of thumb I simply do not head for steep slopes in winter within 48 hours of the end of the last storm. Sure I've missed a lot of great days.

[Seamstress]

The 48 hour rule won't work all the time. It may be unusual in the Cascades, but we do have some persistent unbonded layers out there.

 

I often choose to travel in avalanche terrain during early morning hours when the slopes will be more stable, and be off early. I also may choose ridgelines and spend very little time in actual avalanche paths. I may choose to perform tests on the desired slope before skiing it. I may remain in the bootpack and not venture into the pristine snow. There are many ways to manage risk. That doesn't reduce the risk to zero. I am very conservative, but I do realize that the risk is not zero, and it may be more risk than others are willing to take.

[pcg]

The 48 hour rule won't work all the time.

I didn't mean to infer that waiting 48 hours makes it safe, only that I use it as a first rule of thumb, meaning I don't even think about going skiing on steep terrain until 48 hours have past. Waiting 48 hours is never a green light for me. But not waiting 48 hours is an absolute red light. That doesn't mean I won't get out. I just may head for Zig Zag glacier or somewhere that I can avoid avy terrain.

[Coldfinger]

I would add that all this really is modeling based on selected (read sparse) sampling and not real time data.

 

I get a knot in my stomach sometimes as I know conditions are probably worse than what is being projected.

 

Or put another way, a "considerable" warning could be very very wrong.

[JasonG]

My experience over the years is that often times "considerable" forecasts turn out to be overly conservative and the stability is much better than predicted. Of course, it is that one time that gets you.

[Rad]

I'm not an expert, but it's not too hard to imagine situations (e.g. shifting wind directions, variable cloud cover) where snow stability varies widely within a small area. So no matter what the forecast or hazard rating is one needs to assess the local terrain carefully.

 

Perhaps ice climbing, another sport I haven't taken up due to time constraints and concerns about objective hazards, shares this feature.

[ZimZam]

Slide today in CO

[video:youtube]

[sobo]

Lucky fukkerz...

[ZimZam]

kinda like someone filming the incoming tsunami from the shoreline. Oh fuck