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Avalanche Gear
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Avalanche Gear

 
Avalanche Gear

Page Type: Gear Category

Object Title: Avalanche Gear

 

Page By: T Sharp

Created/Edited: Sep 11, 2007 / Sep 14, 2007

Object ID: 3929

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Avalanche Gear Overview

Avalanche gear is a broad topic that involves 6 different categories of gear into one usable set of tools that will ensure that with practice your partner will be able to find you in case of an avalanche burial, you will be able to find him, and too, you will know current conditions of the snow pack, and if you mess up and get caught you can increase your ability to withstand the toxic atmosphere that quickly builds up in the snow around your head.

All of these tools used as a system will not guarantee that you will not get caught in an avalanche, but they will increase your ability to act proactively in case of burial, and increase your knowledge base of the immediate snow pack, in order to avoid burial in the first place.

The chances of needing your transceiver, probe, shovel, and avalung are increased if you do not have a basic knowledge and ability to analyze the snow pack in your immediate area, and region. So the need to combine the tool set with a basic avalanche class cannot be over stated. You should also avail yourself of the latest avalanche forecast for your area from Avalanche.Org, and or any other local forecasting services prior to each tour.

When it comes to recreating in avalanche terrain, knowledge is your best defense, when that fails, and you or your partner get caught in an avalanche, a transceiver, shovel and probe, and the knowledge of how to use them are all that stand between you, your partner,and certain death.


CATEGORIES include 1]Transceivers 2]Probe Poles 3]Shovels 4]Avalung Breathing Device 5]Pit Diagnostic Tools. 6]Snow Pack Information and Resources

Transceiver Overview

Avalanche transceivers are a dual functioning electronic device that allows one unit to transmit to, and be located by an accompanying unit, in other words they send and receive radio waves. Since almost all transceivers operate on the same frequency, it is possible for any transceiver to locate any other transceiver once a signal is picked up. This is good because there are many competing makes and models available to the outdoor enthusiast. Because the transmission is by radio signal, the hidden unit does not have to be visible to the searching unit, making them ideal for locating people caught and buried under snow. Because the signal strength is relatively weak, [40-90 meters] they will not function well to locate your wandering girlfriends car. If however you are looking for your girlfriend who was just swept away by an avalanche, they are the best chance you have of locating her in time to save your relationship.

When traveling in avalanche terrain, the strongest statement of commitment you can make to your partner is that you will be able to, with the help of your beacons, dig them out of any hole in which they may land! Trust and knowledge that they will do the same for you becomes the basis for a lasting back country relationship.

Since, like relationships, we are not hardwired with the knowledge of how to operate transceivers, it is a good idea to practice. Have your friend hide her unit, then you try to find it, practice can be fun! Do not forget to reciprocate by having her find your unit too! When practicing with your climbing partners, care should be taken as to where you hide your beacon!

All modern transceivers transmit radio waves on a 457KHz frequency. This is the result of a standardization that happened @10 years ago. The original U.S manufactured transceivers transmitted on a frequency of 2.275 kHz and the Europeans used the 457 kHz wavelength. This created a huge problem when they tried to search for each other! Ortovox remedied the problem with a dual frequency transceiver, this was a short lived solution though as the more efficient 457 KHz transceivers won out. The problem with the dual frequency beacons was that the signal strength was split between 2.257, and 457 kHz effectively reducing the signal strength of each wavelength by 50%.

Transceivers work by emitting a radio wave when switched on that is inaudible to the human ear . This signal is transmitted from the antenna in a 360 deg. pattern, so that no matter the position of the beacon it can be located by a receiver will that will emit a "Piep" sound indicating a signal has been received. Since the transmitters are small in size and power, the distance the radio waves travel is very limited, usually about 80 meters.

The three main types of transceivers are 1]Analog 2]Digital/Analog 3]Digital only. Each type transmits the 457 kHz signal via a single antenna for approximately the same distance, rate, and length of time. The differences are in the way in which each type of beacon receives the signal being transmitted, how they process that signal, and the manner in which they tell the user about the signal that has been picked up. There are advantages, to each type of transceiver, so a brief description of each is in order.

1]ANALOG BEACONS; All transceivers transmit an analog signal via a single antenna, analog beacons have a single antenna that receives the signal. The signal strength is usually indicated by an audio "beep", and sometimes a set of LED lights. The louder the beep and the more lights lit, the stronger the signal being received. The most important feature of analog beacons is the volume/range switch that is set in an initial search mode, and moved to decrease volume as you approach the buried beacon. Failure to decrease this volume switch will render the search fruitless, as you will be unable to tell when you are getting closer to the target. Hence the consensus that the analog units require more practice and skill to operate efficiently. Once this level of proficiency is a achieved though the search is every bit as fast as the digitized units. Analog transceivers can have a very long initial search range, 80 meters is not unheard of. Many have an external earphone jack in case of high winds or other distracting noises.

2]Digital/Analog Beacons have 2 or 3 receiving antennas, and a microprocessor that analyzes signal information to determine distance and direction of the strongest signal flux line. This information is usually displayed on an LED screen. Some digital units can distinguish between multiple signals in the case of more than one victim burials, and display and mark individual signals. The digital/analog units still have the long range capabilities of the analog, combined with a computer that turns down the volume automatically, and indicates the distance in meters and direction of the strongest signal on a display that is easy to understand and follow. The switch between analog and digital is usually automatic, and some models will indicate this switch by turning off the audible "piep" when entering the digital mode. You will however need to do a fine grid search [see Basics of Use] when getting very close to the target, [under 3 meters]. The thing for searchers to remember with this type of transceiver is that it takes a bit of time for the processor to relay the info, so especially in fine grid search mode, a count of 1 to 2 at the extremes of the grid will enable the transceiver to "catch up". Deliberate, slower movements work best to quickly narrow the last few meters. These transceivers are also customizable to a certain degree, to fit a searchers preferred technique.

3]Digital only transceivers have a more limited search range, usually 35-40 meters, but once a signal is located, the same basic search technique for digital/ analog is used. Digital units tend to be easy to use, as all you have to do is follow the directional arrow on the display for the displayed distance, and you will be directed to within a 1-3 meters of the victims beacon. This is very advantageous in an emotion filled situation where your friend is buried and you are borderline freaking out. The search times are quick, and almost idiot proof, even a novice when only given rudimentary information about searches can usually find the target. However in order to achieve the quickest search times, which is our goal, you will still need to practice, practice, practice!

Just a few quick words about search ranges, maximum range distances cited by the manufacturers are the result of the transceivers antennas being exactly parallel, and each beacon equipped with new batteries. Real life conditions will likely vary, like if the victim is face down, and the signal has to get through a pack with a metal shovel, or if the victim is oriented vertically, a horizontally held search transceiver will have a hard time locking onto a strong signal from a distance.

PURCHASING
Depending on your level of experience, and your ability to get out and practice, will be the indicators as to which transceiver to purchase. The more sophisticated the transceiver, the more expensive it will be, with the most sophisticated at $465.00, and the most basic models at around$ 200.00. The technologies in transceivers are advancing at a fast pace and it is not unforeseeable when your GPS unit will have an integrated transceiver, cell phone, and emergency locate beacon all in a unit the size of a credit card. The most important thing is ease and familiarity of use of the features on your transceiver.

Major Players in the manufacture and marketing of transcivers are;
Ortovox
Survival on Snow
Pieps
Mammut
Back Country Access
Arva

I personally have 3 transceivers, one dual frequency, {which the dog gets}, one 457 analog, and one digital/ analog, if I am lending a partner one of my transceivers for our tour, she will get the digital analog, because it will be my butt she is trying to find [and I have practiced extensively with the analog model]!

The transceiver is worn beneath your outermost garment, this protects the unit from being torn off in case you become caught in an avalanche, and also helps to keep the batteries warm. Transceivers have a harness system that securely attaches the unit over your shoulder, and around your waist. This harness also aligns the antenna to your body making locating the beacon signal easier. Modern units are robust and sturdy, but you should avoid dropping them, check all functions on the unit thoroughly if you do happen to drop it.


Batteries
Most transceivers operate on 2 or 3 AA Alkaline batteries, these should be replaced at least once a year. Most transceivers have a battery self test, or a meter on the display. If your batteries are showing any sign of depletion, replace them as soon as possible.


Basics of Use
There are two primary ways of narrowing the distance between the transceivers, one is a grid search, the other is by following the tangent arc of the radio wave. It is necessary to understand and be able to perform searches using both techniques, but most modern search techniques will use the flux line method in the primary search mode, and switch to the grid in the fine search mode under 3 meters.

When members of a ski or climbing party start out on a tour or climb all transceivers are set to transmit mode, and one at a time, members pass by a control transceiver set to receive, to check that each is transmitting properly. While on tour, all transceivers should be set to transmit. Most modern transceivers have a "forced on" switch that when rigged to be worn, turns on the device. This prevents the user from inadvertently forgetting to turn on the unit.

If a avalanche takes a victim, all others not affected survey the situation and asses if it is safe to enter into the area of the slide, if so then all units are switched to receive mode, and the transceiver is held out in front in a horizontal position. The initial search begins to seek a signal from the buried victim. Once a signal is found, the secondary search begins, this follows the flux line of the signal to the buried victim, usually within 1-3 meters. Then the final pin-point search begins that will locate the strongest possible signal and indicates the place to probe and dig.

The person who picks up the signal initially will usually become the search "captain", and locate the strongest signal, other members of the party can begin assembling probes and shovels in anticipation of the hard work yet to come. If enough people are available, a look out post should be established to watch for other avalanches that could endanger the search party. A first aid kit should be out along with extra layers of warm clothes, as the victim will likely need immediate care.

Whichever type of transceiver you choose, you will still have to perform a final grid search to pin-point the strongest signal.
The most important thing to remember when doing a final grid search, is to keep the orientation of the transceiver the same as when you came to the shortest distance on your display, or reached the lowest volume level . Do not wave the unit, but rather move the unit laterally for a few inches until the signal become obviously weaker, mark this spot in the snow. Now move the unit laterally the opposite direction until the signal weakens again, mark this spot too. From the point directly in the middle of these marks move the unit forward until the signal becomes obviously weaker, mark this spot. then move the unit back until the signal is weaker, mark this spot. Where the two lines [created by your marks] intersect will be the strongest signal, and the place to probe and dig. Holler at your buddy that you are coming to get him and then dig like hell!

The search should all be completed within a very few minutes, as any burial that lasts longer than 15 minutes will likely result in a victim that is extremely hypothermic, suffering from blunt force trauma, and suffering from carbon dioxide [and other toxic gasses] poisoning from breathing their own exhaled air. In a back-country situation these conditions will be life threatening, so speed in searching is of the essence. Strive to locate the buried transceiver in less that 3-5 minutes in your practice sessions. People who practice a lot [enough] can regularly locate the beacon in less than one minute, this is ideal. Remember that digging in avalanche debris will be very difficult and time consuming, so you will want to conserve as much time as possible for this labor.

One last thing to remember, once you have located the victim[s], all of the transceivers in the party should be switched back to transmit, in case of another avalanche coming down. Some digital units do this automatically after a set period of inactivity.

This is a lot to keep track of, and it really does not even scratch the surface of the basic knowledge necessary to travel safely in avalanche terrain. Take an avalanche training course, update your skills constantly, and keep your head on straight when traveling on snow covered slopes greater than 25deg. .

There has been some discussion about multiple burials, but this breaks one of the most basic rules of safe travel which is to expose only one person at a time to avalanche terrain. If there are multiple burials, major mistakes have been made!

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