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Avalanche Rescue - The Search
Avalanche Rescue - The Search
For the members of a group who witness an avalanche and the capture of another person by the sliding snow, an ensuing rescue can prove to be daunting and overwhelming. It’s best to slow down and methodically plan, even if it takes 10 seconds, and proceed with as much intention and deliberation as possible.
Outlined below are likely stages of a search and key elements for consideration. It is vital to review this outline before ever encountering an avalanche accident. Practice with your partners and rehearse in your head the step-by-step process.
The stages of an effective rescue are BOLD while the recommended actions are italicized
Point Last Scene (covered in Tour Practices) Ideally you were able to watch your partner in the moments before they were grabbed by the moving snow. Where were they when you last had a positive visual sighting? This is the Point last Seen, and it is crucial: this is where you will begin your search. If they were moving with the snow, then they will be below this point. Avoid searching higher, as there is little evidence that they would be buried uphill of the point last seen.
Appoint a leader Think of a time when you worked in a group and things went well. Was there an obvious leader? Probably. This is not necessarily the best transceiver-searcher or even the most experienced skier. It should be the person with some calm, methodical manner that can manage any emerging chaos and organize the scene, as outlined below. Sometimes it is best to even appoint a rescue leader before proceeding into the backcountry. Why wait to organize in the chaos when you can begin before it is even necessary?
Scene Safety Before you proceed, check the environment:
Is everyone else accounted for? How many people will you be searching for? Is there any remnants of the slab still hanging on above you? Can you proceed with the search within a reasonable amount of risk? If you begin the search, what is the likelihood you may get caught in another slide of some other hazard?
Plan “Go slow to go fast” as they say. Take a moment and develop some plan. Do not proceed into a rescue without communicating to your partners, others, - even just yourself - a semblance of an ordered plan.
Appoint Roles There are many roles in an effective search. Ideally, a group is large enough to cast a member in each role. However, often those size groups prove more challenging as their size complicates communication and travel and often lead to avalanche situations.
Surface / Debris Search
In the case there are enough people, this process should be a priority. Proceed to any obvious debris (gear, clothing, items from the buried person) and immediately probe the area.
Leave items where they lie
Do not remove or move any surface item, whether its been probed or not. The act of probing is not exact, as you’ll learn. To find someone buried through probing is a painstaking process that requires patience and diligence. Leaving surface items ensures you are able to return and re-probe an area.
Inventory the Search
Be certain there is a running log of what has occurred during the search. This is a great task for a leader. What’s been searched? What’s been found? How many people are buried? Where was the point last seen.
Transceiver Search
In accordance with your plan, conduct an efficient transceiver search. Consider in your plan the area to be covered and the resources (people) to conduct a search in that area. Your most efficient transceiver search may not require more than 1 or 2 people.
Switch mode of Rescuer Beacons
It’s challenging to conduct a transceiver search if you have to wade through the signals of people who are not buried. A good task for the leader is to remind people to turn to “Search” mode, even if they are not conducting the actual transceiver search. Do not turn them off!
Probe Search
Finalize your pinpoint stage of the transceiver search and begin probing. For efficient and strategic shoveling, it is essential to probe and discover the location (place and depth) of the person.
Shoveling
Get into an organized team and strategically move snow in a precise effort to excavate the person.
Triage
Do not expect to be done with the rescue once the person is unburied. In many cases, you will need to assess the person and initiate some level of first aid.
A Quick Avalanche Rescue Checklist
A Quick Avalanche Rescue Checklist
Identify Point Last Scene
Appoint a leader
Determine Scene Safety
Make a Plan
Appoint Roles
Conduct a Surface / Debris/Obvious Containment Search
Conduct a Transceiver Search
Conduct a Probe Search
Strategically Shovel
Perform Triage
Avalanche Rescue - Timeline of an Avalanche Accident
Avalanche Rescue - Timeline of an Avalanche Accident
Presented below is a possible timeline of being caught in an avalanche, as presented originally by Bruce Tremper in Staying Alive in Avalanche Terrain. Much of what occurs while being caught happens in the first few minutes. After 4 minutes, a victim is racing against the clock for usable air.
For victims buried without traumatic life-threatening injuries, it becomes a matter of having adequate gases to inhale. It’s not so much an absence of oxygen, but rather the increased presence of carbon dioxide. How long could you hold your breath?
Recall the statistics about survival rates? Many people don’t survive regardless of the amount of time buried.
At Time ‘0’ –
you may hear a ‘whumph’, or even feel a rush of air out of the snow pack;
sometimes there will be a loud crack;
cracks appear in the snow pack!
1-2 seconds
the snow starts to move;
feels like someone yanked the rug out from under your feet
most people fall down
the slab begins to break up
after 2 seconds the snow is moving at 10 mph.
If you don’t take IMMEDIATE action it is too late – you must already have an escape plan and be acting on it.may hear a ‘whumph’, or even feel a rush of air out of the snow pack;
sometimes there will be a loud crack;
cracks appear in the snow pack!
2-5 seconds
snow is moving 10-30 mph;
blocks are tumbling furiously;
skiing becomes impossible
skis often become an ‘anchor’ dragging you deeper
a snowboard’s larger surface area may cause it to slow and float to the surface spinning you head-first downhill and driving your head deeper
hopefully your bindings release!
you are moving fast enough to be seriously injured or killed.
5-10 seconds
avalanche is moving at 40-80 mph;
you have no idea what is up and what is down
you try to breath but you suck in snow not air
it forms a plug in your nose and throat
impacts with rocks or trees are bludgeoning you to death
‘swimming’ for your life may allow you to stay on or ‘in’ the surface if you are lucky.
10-15 seconds
The slide begins to slow
try to swim hard against the flow with the hopes of being pushed to the surface
as it slows further try to clear your airway
try to clear an air pocket in front of your face and expand your chest as much as possible.
The avalanche stops
all is dark and quite
the debris sets up like concrete
you are frozen in place and can not move
if you are completely buried the weight on the body and chest is significant, possibly unbearable as it compresses your chest and limits your ability to breath.
4 minutes –
As you re-breath the CO2 that builds up in the air pocket and the surrounding snow you begin to lose consciousness.
15 minutes
Most burials will still be alive but unconscious
there may be internal injuries
an ice ‘mask’ has begun to form around the face decreasing the ability to draw air from the surrounding snow.
25 minutes
Half of completely buried victims will be dead.
35 minutes
73% of completely buried victims will be dead;
anyone who survives after this time must have a significant air pocket.
90 minutes
81% of victims are dead.
130 minutes
97% of victims are dead
anyone who survives beyond this must have an air channel to the surface.
This timeline is from Tremper, B (2008). Staying alive in avalanche terrain. 2nd edition. The Mountaineers,; Seattle, WA. p. 246.
Timeline adapted from Wing Ridge Tours avalanche course materials developed by Roger Averbeck
Avalanche Rescue - Post-Burial
Avalanche Rescue - Post-Burial
In many instances, an avalanche victim may need immediate and serious medical attention. The skills taught in Avalanche safety courses stop at the burial and recovery. In order for any backcountry traveler to be effective in their rescue, it is imperative to possess wilderness medical training.
There are several levels of wilderness medical training, beginning from a very basic first aid course to the extensive emergency medical technician course.
For anyone travelling in the backcountry, knowledge about the complexities of extensive medical care is essential. In many cases, a simple unburial of an avalanche victim reveals a litany of issues that must be addressed. For some, the consequence of an avalanche may be relatively benign (non-life threatening); however, a simple injury in the backcountry is exacerbated by distance and limited resources. Suddenly that sprained knee that cannot bear any weight results in a need for care and monitoring. The simple hour skin out is now impossible, as your partner lacks the ability to move and care for themselves. As well, the immediate care of injuries provides support toward healing and mitigation of long-term consequences.
Alongside any avalanche safety education folks must procure some level of wilderness medical training in order to be better prepared for backcountry incidents.
Challenges of the Multiple Burial
Challenges of the Multiple Burial
Double Burial vs. 3+ burial
Double Burial vs. 3+ burial
It seems in most cases that burial becomes increasingly challenging with the addition of more victims. A two person burial is more challenging than a single; but less than the degree of challenge when a third or fourth are added. The presence of 3+ signals during a search can become overwhelming. Add close proximity burials, and a rescuer can become truly flummoxed.
Serial Searching
Serial Searching
The basic premise of a multiple burial is to continue along with a serial search. Find one signal, then proceed onto another one. Whether using technology or method, this focus on finding one at a time may assist in slowing a rescuer down, and then becoming more efficient. It takes practice to listen to one signal while ignoring the others that are being picked up. We strongly recommend understanding your transceiver’s technology and using it to your advantage. This technology will allow you to proceed through a search in a serial method, proceeding from one signal to another.
Specific Search Methods for Multiple Burials
Specific Search Methods for Multiple Burials
Three Circle Method
Three Circle Method
Avoid this method. While simple in theory, it proves to be quite challenging when attempting to move slightly away from one signal while looking for another. With transceivers indicating multiple signals, the premise is to move away from a first found signal in an increasing radius while focusing on signals from unfound transceivers. As the radius increases , the unfound signals should decrease as the found signal decreases. It relies on an ability to discern between signals, which at some point may be equal.
Microstrip Method
Microstrip Method
In the case of excluding technology and relying on method, the microstrip is the most user-friendly method. It continues with a strip pattern search, but reduces pace between tracks to a much smaller area. Rescuers proceed to 1-2 meters from the edge of a slide path and then “drop” only 2-3 meters before proceeding back across the slope. This “microstrip” allows the rescuer to focus on low numbers and ignore any signal that does not register below a threshold. A challenge to this method is determining that range. For seep burials, it may be difficult to effectively differentiate a signal as depth distance and not just horizontal location distance.
The Technology
The Technology
Many modern transceivers are made with specific functions toward improving a multiple burial scenario. In this case, it is important to understand the intent of each function. The general principle of a flag/marking/suppression function is to isolate signals, so the rescuer may concentrate on a single burial. There are various methods to achieve this, depending on the make and model of your transceiver.
It seems that Ortovox has a suppression feature, which eliminates the strongest signal, assuming you’ve located that person and have not had the opportunity to turn their transceiver off. The basic process is to follow the strongest signal, once located, turn on the supporesion, which will then highlight the next signal, and then proceed to the next victim. This works great so long as there is a clear distinction between burials. It will prove quite challenging on close burials.
The trackers have various functions. The old trackers have the SP function, which suppresses the strongest signal and supposedly only searches a close range for a second signal (within 20 m). If another burial occurs outside that range, the recommendation is to continue a modified strip pattern until you get close enough to pinpoint a second burial. The BP function on Tracker 3 is a scan feature , which reads every specific signal it receives and indicates direction and distance of each. This can prove confusing, but seems to be designed for a micr-strip search, where you simply focus on the Analog (distance readout and sound).
Problems with Marking Features
Problems with Marking Features
Marking functions of transceivers are not 100% reliable. Common problems encountered when attempting to mark a signal may include:
Transceivers not recognizing all buried transceivers.
A signal unable to be “marked” due to overlapping signals or an inability to recognize a distinct signal.
The performance of the marking feature decreasing when there are four or more signals.
A marked signal becoming unmarked, resulting in the same burial being found again.
Reduced receiver range once a signal has been marked.
Misleading directional arrows once a signal has been marked and other signals are present.
Non-error-tolerant marking strategies; failure to mark a found device may result in the inability to continue with an additional coarse or signal search.
Signal Overlap. Overlapping signals are one of the biggest challenges for transceivers in multiple burials. When signals are overlapped, no useful information about the second signal is available to the device. The only option is to wait until the signal overlap resolves itself, which can take up valuable time.
Signal overlap explains most of the above-listed shortcomings. Other reasons that cause issues in recognizing multiple signals are:
Variations in frequencies (older devices).
Receiver band width (may not recognize a device with a drifted frequency).
Constant carrier signal as a result of local interference or analog technology (may be interpreted as a distant signal).
Ineffective search strategy (failure to apply systematic search pattern, or poor balance between search speed and search precision during the different phases of the search)
Sourced from https://williamskeaclimbingphotography.com/resources/caa-avalanche-search-and-rescue-course-summary/lesson-6-multiple-burials/
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