Joined: 06 Dec 2004 Posts: 268 Location: Beautiful British Columbia
Posted: Sat Dec 11, 2004 4:45 am Post subject: How do avalanche victims die?
The question of how people buried in an avalanche die has been a matter of some debate for years. It is an important question, though, because it really affects risk management strategies; for example, if a high percentage of victims die due to physical trauma, then we really need to put much greater emphasis on avoidance, rather than teaching people how to use transceivers efficiently.
One problem with this topic is that it is very difficult in many cases to determine exactly how someone died. Also, in the panic following an accident, evidence that could help answer this question (e.g. the extent of the ice mask around a victim's mouth) is lost. Too often, I suspect, a Coroner or an autopsy will not examine this question in detail, and just assume that a victim died of asphyxiation, when in fact the primary cause of death might have been trauma.
In unserer Schadenlawinendatenbank ist die Todesursache im Zeitraum von 1980 bis 2001 für das freie Gelände folgendermassen verteilt:
18% Mechanische Verletzungen
In einer Studie von Weymann, 1999 (CH-Daten 1991 bis 1996), bei der auch die Personen von "Katastrophen-Lawinen" berücksichtig sind, ist folgende Verteilung aufgeführt:
43% Mechanische Verletzungen
My translation is that Dr. Steiniger is quoting one study that examined accident statistics at the SLF from between 1980 and 2001 and concluded that 18% of victims died due to trauma, 24% due to asphyxiation, 2% due to hypthermia, and the rest were unknown. This is rather startling, because it suggests that trauma accounts for almost as many deaths as asphyxiation.
If the "unknown" deaths had the same proportion of trauma vs asphyxiation deaths, then 24% of these were trauma, which would mean that 42% of the total avalanche deaths reported could be due to trauma!!
His second study of victims buried in large avalanches between 1991 and 1996 found that 43% died of trauma and 46% due to asphyxiation.
Based on my own analysis of studies over the years, I have usually assumed that about 1/3 of avalanche deaths were due to trauma. Based on these new figures, I think it is safe to say that as many as about 40% of avalanche deaths could be due to trauma, and we really have to re-visit the risk strategies that we are employing.
I will stop here to see if one of our German friends can first of all ensure that my limited abilities at German translation are correct, and then wait for comment. _________________ There are no easy solutions, only intelligent choices
Joined: 06 Dec 2004 Posts: 536 Location: Squamish, BC
Posted: Sat Dec 11, 2004 5:30 pm Post subject:
For those who died from trauma, I would be interested to know in how many cases trauma to the head was the cause of death.
Many backcountry skiers do not wear helmets, while these same skiers will wear them at the resort.
In other words, do the stats, if they are available, make a strong case for wearing helmets in the backcountry? _________________ We need wilderness because we are wild animals. Every man needs a place where he can go to go crazy in peace.
- Edward Abbey
Joined: 06 Dec 2004 Posts: 268 Location: Beautiful British Columbia
Posted: Sat Dec 11, 2004 10:20 pm Post subject:
There is no mention of helmets. Another point to add to this discussion is that Werner Munter maintains that at least one third of avalanche deaths are due to trauma, and that we must make more efforts to help people AVOID hazardous situations. Of course, that is what his 3x3 Reduction Method, the German Snow Card, and other risk-based systems seek to try and do.
This information can also be used when deciding what rescue gear to consider. Using transceivers or avalungs, for example, doesn't reduce the chances of succumbing to trauma. Interestingly, the ABS Backpack, which keeps you on top of the snow due to buoyancy and particle separation, may help reduce trauma deaths- as long as you don't go over a cliff, into a crevasse, or are strained through trees.
The bottom line is still the same: focus on terrain and routefinding to AVOID dangerous places. So what are you doing on this thread- go over to one of the excellent picture/routefinding threads or, better still, get out there tomorrow on a tour with someone who knows their stuff and can teach you to stay alive. _________________ There are no easy solutions, only intelligent choices
Joined: 11 Dec 2004 Posts: 78 Location: Calgreedian
Posted: Sun Dec 12, 2004 12:32 am Post subject:
great stuff here, i can't remember where, but i have read stats very similar to those some time ago. it's a great thing to bring up with people that are gung-ho to go hit up steep lines and such just cause they got a transciever strapped to them. I think the majority of people out there don't think about the possible trauma side of things, for myself thats whats #1 in my mind.
you could sustain many types of injuries, depends on the terrain,
- are there shallow rocks
- uneven surfaces
these all could help induce severe injuries. thats my two cents for now.
btw, pre ttips crash i was telesnowboardguy, thanks AVAB for the tips on running RAC courses, thats definetly the direction i was heading in, would've posted sooner but work kept me busy.
Joined: 06 Dec 2004 Posts: 324 Location: Nederland
Posted: Sun Dec 12, 2004 9:25 am Post subject:
Shouldn't one include all avalanche victims that survived in these stats? I mean, that would really reduce the percentage of people who died from mechanical impact. At the other hand, I don't know how many of these survivors suffer some impact damage, like broken bones, concusions, twisted knees and thelike.
Joined: 07 Dec 2004 Posts: 116 Location: Chartreuse Mountains
Posted: Sun Dec 12, 2004 5:17 pm Post subject:
Ava Blanche wrote:
Another point to add to this discussion is that Werner Munter maintains that at least one third of avalanche deaths are due to trauma
I tell people I talk to that the figure is 25%. This often shocks them because the nice rinky-dinky survival curve gives you the impression that if your buddy digs you out quickly enough all will be well:-
Here are some figures for France from the police investigations and compiled by Fred Jarry at the ANENA:
Avalanches killed 26 people in France during the 2003-2004 season. 107 people were involved in these accidents and 37 buried. Apart from the 26 deaths a further 28 people were injured.
The figures for the last two years are lower than the average over the last 15 years. This trend is partly due to the drop in the number of victims amongst snow shoers and ski tourists with 9 deaths as opposed to 15 the previous season. Amongst the completely buried victims, 12 (5 alive and 7 dead) were found thanks to their avalanche beacon, 9 by an organised rescue using probes (1 alive, 8 dead), 5 due to dog search (1 alive and 4 dead) and 4 thanks to signs on the surface of the snow (1 alive and 3 dead).
Okay it is a limited data set but it tells me that an avalanche beacon is an important tool but it maybe only doubles your survival chances.
17% chance of being found alive not wearing a beacon.
42% chance of being found alive wearing a beacon.
So probably around 4 to 5 deaths were due to the extra delay in being rescued through not having a beacon.
Of the other deaths a number must be due to delay, perhaps due to lack of practise in search and rescue but a big part must be through collisions with rocks and trees and crushing. Having turned this over I think Munter's figure could well be accurate. _________________ PisteHors.com
Joined: 07 Dec 2004 Posts: 152 Location: 9,300ft ASL
Posted: Sun Dec 12, 2004 8:27 pm Post subject:
I am surprised nobody really considers armor beyond a helmet.
Don't you think a spine protector, armor jackets, armor pants, etc (hard + soft) could reduce the severity of trauma in an avalanche in many cases? _________________ It is what I would do if it were me. It is not me and neither are you.
Joined: 06 Dec 2004 Posts: 268 Location: Beautiful British Columbia
Posted: Mon Dec 13, 2004 4:02 am Post subject:
Thanks for the info, Carl. In my experience, this has been a somewhat controversial subject, and so it is heartening to see that there is wider agreement that at least 1/3 of avalanche victims die due to trauma.
A very good and respected WEB site that discusses avalanche deaths and rescues in more detail is one provided by the International Commission for Mountain Emergency Medicine (ICAR) http://users.south-tyrolean.net/avalanche/index.html Scroll to the bottom of the WEB site and check out the information for skiers and rescuers; there is an amazing amount of good, scientific information on this site.
1. Wrong: Uninjured group members leaving the avalanche site too early. Right: Intensive search for 15 minutes using eyes, ears and avalanche beacons.
2. Wrong: Unnecessarily approaching the avalanche site. Right:Approach the avalanche site only to locate, dig out, or take care of the victim.
3. Wrong: Removing the avalanche probe after a possible find. Right:After a possible find, leave the probe in the snow.
4. Wrong: Digging vertically to find a victim. Right: Dig a large sloping rescue pit from the side. Here is an explanation of the rationale behind this:
Don’t dig vertically but obliquely from the side, in order not to destroy a possible air pocket. When the victim is found, determine the orientation, free the head using your hands, and protect the victim’s face during the extrication so that snow cannot block the airway. The rescue pit must be large enough to allow at least one rescuer to work in it and begin the first life-saving measures.
5. Wrong: Notifying the emergency doctor only after the victim has been dug out. Right: Call the emergency doctor immediately after locating the buried victim.
6. Wrong: Not paying attention to an air pocket and to the airway. Right: Check the space in front of the mouth and nose; evaluate the airway.
7. Wrong: Making large movements of the victim’s body during extrication. Right: Extricate the victim as gently as possible.
8. Wrong: Not placing an unconscious victim on one side. Right: Place an unconscious victim, who is not intubated, on one side.
9. Wrong: Resuscitating snowmen (victims who have no chance of survival). Right: Follow the ICAR triage guidelines.
10. Wrong: Discontinuing resuscitation of a victim with an air pocket. Right: HYPOTHERMIC AVALANCHE VICTIMS WITH AN AIR POCKET ARE NOT DEAD UNTIL THEY ARE WARM AND DEAD.
There is also a section dealing with the ABS Airbag and the Avalung:
In an avalanche, the skier can avoid being completely buried by reducing the total density of the skier-balloon unit with respect to the snow density and by using physical effect of "inverse segregation” (larger grains remain on the surface (15)), so that the deep-snow skier or the backcountry skier is only partially buried or remains on the surface of the snow.
During the period 1991-2002, 40 cases were documented in which people with airbags were caught by avalanches. Of these, 39 survived. One person was buried with fatal results in spite of the fact that the airbag deployed. In order to be buoyant, it is necessary that a skier be carried a short distance by the flow of an avalanche. If a person is trapped in avalanche debris and is buried by a second avalanche, buoyancy is no longer possible.
The Airbag lowers the risk of complete burial from 39% to 16.2% and reduces the mortality rate from 23% to 2.5% (16). Based on these statistics, at the present time, the airbag is the most effective safety device for decreasing mortality due to avalanche burials.
Here is a comment on the Avalung:
The AvaLung TM was developed in 1996 by Thomas Crowley and Black Diamond Equipment Ltd. in Salt Lake City, UT, USA (17). The device is built into a vest or harness, worn over the torso when travelling in areas that are not controlled for avalanches. If an avalanche is triggered the user must put the mouthpiece in the mouth and breathe through it while buried. A one-way valve allows inhalation from the surrounding snow and exhalation to the rear of the vest. This provides an artificial air pocket and avoids a build-up of carbon dioxide in the inspired air.
From 33 successful tests so far, one can conclude that a completely buried person can survive with the device for up to an hour. So far, a few burials with AvaLungTM have been documented in which the victim survived. However, the International Commission for Mountain Emergency Medicine does not yet recommend using this "rescue vest.” Additional cases are needed for a definitive assessment.
It remains doubtful, primarily, how many of those wearing the AvaLung will be able to position the mouthpiece correctly in an emergency.
The most serious disadvantage of this system is the fact that use of the AvaLungTM implies acceptance of a complete burial with all its risks. Timely rescue, even with a prolonged period of survival cannot be guaranteed.
Another excellent source of information is the Swiss Federal Institute site at http://www.slf.ch/avalanche/avalanche-en.html Note that they have an English version. If you scroll down to near the bottom, you will see an excellent information sheet titled "Caution Avalanches", which can be downloaded in pdf format.
There is an excellent forum on the SLF site- unfortunately, most of the discussion is in German. Then there is this funny cartoon on the SLF site:
Finally, since Knox Williams is retiring after this season, I thought it would be worth bringing one of his beautiful little succinct articles on avalanche safety to everyone's attention http://www.cmc.org/cmc/eightstp.html _________________ There are no easy solutions, only intelligent choices
I was in Salt Lake city this past weekend, lots of unusually heavy snow for this area combined with faceted underlying layers/rain/warm temps combineing for ratings in the HIGH catagory Thursday thru Sunday.
In spite of this well publisized information as of Sunday morning two people had perished in the backcountry....one skier (wearing a beacon) and one snowmobiler (wearing a beacon) there was also a successfull recovery of a snowmobiler wearing a beacon. In addition two snowshoers were unacounted for with a report of tracks leading into avi debris (as of Sunday am)
The snow was unusually heavy for this area with about 6-7inches of water in roughly 3 feet of snow (depending on exactly where in the range you were) after it had cooled and set up the slabs were in the two to four foot range and very dense.
Pretty clear at least in this storm cycle that wearing a beacon was NO guarentee of saftey and the best thing to do was stay at the resorts for your ski fix with 66% of reported burials dying while wearing a rescue beacon and recoveried in a timely manner.
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