danhelmstadter Posted September 29, 2009 Posted September 29, 2009 (edited) I plan to study several Mountaineering related accidents so I can learn from them, posting this here seems like a good idea so that we can share and learn from our combined knowledge. Photo and graphics by Fred Spicker - photo taken from Summitpost.org 8/29/08, Mt. Athabasca, standard North Glacier route. Sometime roughly between 9am-4pm - two German climbers: Ulrich Bohne and Josef Rademacher got caught in 80 cm slab avalanche on a ~33dg north facing slope, and ended up dead and buried two meters deep in a crevasse. Conditions were new snow over old frozen snow/ice. Unfortunately the CSAC does not share incident information without 35$ membership... I was unable to find much useful data about the incident, a Summitpost forums discussion, a local news article, and a Summitpost route description. Without more specific details such as temperature, type of snow(slab), exact time of avalanche, and time of sun exposure (if there was sun at all that day), time and weather since storm; it is hard to really analyze this accident, although certain facts of the incident are clear, and I feel these facts pertain to summer or early season situations in our local mountains. In the Colorado Rockies - such early season scenarios as new snow over glacial ice/smooth firn exist, but the development of depth hoar and faceted layers is much more of a concern for them. For us -- we have plenty of glaciers and firn, plenty of potential for such an accident as the one in examination to occur... I feel I have become a little complacent in my ambitious planning and I want to check myself... The Park Headwall for instance while being of a steeper nature -- is a perfect example of a slope which is now ice/firn, but after a few storms -- it could potentially be an excellent ski descent, and it has yielded excellent powder skiing for others in Octobers past, yet the potential for a new snow --- old snow avalanche definitely is there. Of course applying knowledge (such as snowpack evaluation) to specific situations is the key, but the particular scenario of early season lanches because of new snow / old snow interface is a topic which I feel deserves closer scrutiny. It sounds like the German climbers perhaps should have waited a day or two longer -- for the recent snow to settle and form a stronger bond with the underlying surface. Also the Germans should have perhaps done their climbing a little earlier in the day, because considerable new snow on a 30+dg slope in AUGUST SUN is a bad recipe, however while the warm days and sun make the short term daylight time much much more dangerous than say a winter storm event -- the August warmth and sun definitely stabilize the snow a lot more quickly given a few days - the early morn should be money... Also summer snow storms tend to come in warm -- meaning the very first flakes bond better to the old surface than if the storm were to come in cold. I wonder if the Germans knew the basic warning signs of the avalanche; they could have been doing things by the book -- and just got unlucky... What is a good way to go about assessing early season conditions like this --- new snow over the ice/firn ?? I would say do the usual pits, watch for signs, pay attention to the facts of the situation (how much new snow etc...) make a ski cut, but what else??? What would you have told the Germans had you been a ranger encountering them as the left the trailhead? What would you say would be an acceptable enough clue of new snow / glacial ice bond to give you the green light? I would appreciate any input you may have. Thanks, My respect goes out to the fallen, and my condolences to their families. Edited September 29, 2009 by danhelmstadter Quote
fas Posted September 29, 2009 Posted September 29, 2009 Instead of just taking a photo from elsewhere and then depositing it into your "own" album for linking, how about linking to the original or at the very least giving the person who took the photo and created the graphics credit when and where you post it? Photo and graphics by ............ In this case Fred Spicker - photo taken from SummitPost.org http://www.summitpost.org/view_object.php?object_id=30634 Quote
danhelmstadter Posted September 29, 2009 Author Posted September 29, 2009 (edited) good point, i try to be big on respect, i will edit it in. i need to pay more attention the rules and regulations of posting others pictures, in this case i put it in a webshots folder of mine labeled NOT MY PICTURE, but giving credit to the photographer under the posted picture is definitely called for. thanks Fas ******************************************************************* edit note: I remember seeing a crown from a distance above the large crevasse maybe halfway up the Coleman Headwall last week during my hike up Baker last week, this being an example of an N-WS-R3-D2-I -- (((N (natural trigger), WS (Wet-slab), R3 (medium relative to path), D2 (Could bury, injure, or kill a person.), I (The avalanche released at the new snow/old snow interface.))) It was a sobering reminder to keep my head up and snow sense on this time of year when Avalanches are not fresh on the mind. The release of the CHW avalanche noted was almost certainly due to the very warm temperatures experienced after the recent Labor Day snow storm, perhaps the trigger was aided by rock/ice-fall. The CHW avalanche is easy to figure out, evaluation and answers will no doubt get trickier as fall progresses.... The codes I used to classify the CHW avalanche - can be accessed here -- as well as a wealth of other very useful - AIARE standard material. The American Avalanche Association's website is a great resource. Edited September 29, 2009 by danhelmstadter Quote
bstach Posted September 29, 2009 Posted September 29, 2009 Unfortunately the CSAC does not share incident information without 35$ membership... Do you think $35 is too much for this information? CSAC is a non-profit that can use all the support it can get. Don't be so cheap. Quote
danhelmstadter Posted September 29, 2009 Author Posted September 29, 2009 (edited) Bstach -- Thanks, you are right -- I drink pbr and live in my truck, I am cheap, and I am American. If I frequented Canada more - I would definetly pay the membership fee - as it is, I am still saving money for the passport fees... I try to give back to avalanche organazations by submitting my detailed snowpack observations... Edited September 29, 2009 by danhelmstadter Quote
Pete_H Posted September 29, 2009 Posted September 29, 2009 Unfortunately the CSAC does not share incident information without 35$ membership... Do you think $35 is too much for this information? Instead you impose on the kindness of strangers. CSAC is a non-profit that can use all the support it can get. Don't be so cheap. I think you should take your $35 and buy yourself a big bag of shut the fuck up. Dan isn't imposing on anyone, just asking good questions and posting very solid avalanche analysis based on his own research and personal experience. Quote
bstach Posted September 30, 2009 Posted September 30, 2009 Bstach -- Thanks, you are right -- I drink pbr and live in my truck, I am cheap, and I am American. If I frequented Canada more - I would definetly pay the membership fee - as it is, I am still saving money for the passport fees... I try to give back to avalanche organazations by submitting my detailed snowpack observations... Thats fair enough. In retrospect my comment was a bit harsh and judgmental. Please accept my apology. I just want to encourage users to support CSAC for the great service it provides the community. CSAC almost closed down at one point due to lack of funding. Quote
Choada_Boy Posted September 30, 2009 Posted September 30, 2009 I would have talked to them in German, but I don't know German, about potential avalanche hazards and their bad idea. I was up there one winter and a Russian Mom with her Son and Daughter were going for that route in full-on winter conditions, blizzard and all. We tried to explain to them at the Hostel before they left that they had a really bad idea but they looked at us funny. They came back early the next evening after a clearly interesting day, thankfully. Quote
danhelmstadter Posted October 2, 2009 Author Posted October 2, 2009 (edited) I forwarded this post to a friend down in C-lo, he sent me some very insightful comments. Pertaining to the Athabasca incident -- and I don't think he'd mind me quoting him on this - "Rough textured ice with warm snow shouldn't be the failure surface, more likely to be above there in a colder faceted layer (nighttime snow) that was part of the storm but maybe not the beginning? And was there already a snow cover on the ice?" He also mentioned that he had asked several avi-pros in the past about basal facet developing on glacier ice, and they had said that basal facets need a relatively warm ground for formation, and the ice is far from warm. To quote him again "I’ve seen some surface facets growing around big crevasses where there is water running under the glacier and the moisture evaporates and then grows crystals on the surface but that is on very limited surface areas that could only cause tiny slab failures around those cracks." * Small slabs around big cracks = trouble for non roped travelers eg - skiiers thanks man ! ******************************************************************* I'm sure the line is not fine between smooth and rough glacial ice, but I wonder what the point of roughness is - that coupled with a warm start to the storm -- would form a fairly strong bond? What would you classify rough ice as? or to rephrase that -- what is the minimal degree of roughness that you would speculate would create a strong bond? (assuming you speculate ;-) A slightly different angle to the matter of ice/snow interface stability - what is the tendency of the nature of water percolation from above snowpack onto buried glacier ice? does the water tend to coat the surface of the ice sheet and run down broadly - or does it find channels and holes? This is a pretty general question -- obviously subject to many variables -- but It can be answered generally too. What do you feel are a few dangerous avalanche scenarios that are specific to glacier slopes? Edited October 2, 2009 by danhelmstadter Quote
danhelmstadter Posted October 2, 2009 Author Posted October 2, 2009 (edited) I will answer one of my own questions to think "out loud". I don't pretend to know it all, and I'd definitely appreciate your input on this question as well as the others I've posted. What do you feel are a few dangerous avalanche scenarios that are specific to glacial slopes? 1) The terrain trap of a crevasse bershrund at the bottom of the slope. A minor or small slab that would otherwise entrain you through a gentle runout on a non-glaciated slope will kill your ass on a glacial slope, and definitely minimize if not completely eliminate the possibility of rescue -- if you are buried deeply in the crevasse. 2) The threat of full-depth-snow release on a lubricated or smooth glacial slope. 3) The glacial slope with an open bergshrund or crevasse at the bottom creates an unsupported hanging slope --- no compressive strength quality --- much more likely to slide with failure... 4) Only applicable to some mountains --- but glaciers tend to be more prevelant on north and east aspects, which tend to be problem aspects in our northern hemisphere. East = wind-loaded, North = no sun to help stabilize. It seems like a north facing glacial slope as my friend had mentioned might be less likely to form depth hoar - because the temperature gradient would be less severe than if the snow fell on relatively warm rocks/earth -- so that would actually help to reduce the hazard of deep slab depth hoar related avalanche... 5) (Factor that might contribute to instability under certain conditions) The snowpack has no anchors on a glacial slope -- many non glacial slopes are anchored to boulders, rocks, small trees etc... This would probably increase the rate of creep, and make a full depth release with the aid of lubrication or early season weaknesses more likely than on anchored slopes. 6) Slight glacial movement could perhaps stress snowpack structure, and initiate tensile failure??? Edited October 2, 2009 by danhelmstadter Quote
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