Avalanche Search Techniques
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Mammut Pulse Avalanche Beacon
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Technical noteOverloadAvalanche transceiver search techniques vary depending on the number of antennas in your beacon. Multiple-antenna beacons display a direction indicator that points the way to the victim whereas single-antenna beacons have you locate the victim by manually searching for the strongest signal. Many of the instructions on this page apply to both types of transceivers. However, the coarse search explained on this page (where you follow the direction indicator) requires a multiple-antenna beacon. Be sure to read the owner's manual that was supplied with your transceiver and to practice regularly!

CompareThe information on this page is divided into things to do before you leave the trailhead, what to do during and immediately after the avalanche, the signal search that helps you locate the first signal, the coarse search that gets you within a few meters of the victim, and the fine search which puts you over the victim. Remember that probing (aka pinpointing) is an important skill and shoveling takes a significant amount of time.

Before Leaving the Trailhead

  1. Have good, high-quality batteries in your transceiver.
  2. Test your (and your partner's) transceiver. Always carry sturdy avalanche probes and a shovel.
  3. Wear your transceiver under your outer layer where it cannot be damaged or removed by obstacles (such as trees and rocks). Your pants pocket may be acceptable (although it may be more susceptible to impact damage).
  4. If you remove clothing due to warm weather, remember to keep your transceiver under your remaining clothes.
  5. Turn off your cell phone (if practical).
  6. Use safe travel techniques (e.g., route selection, only expose one person at a time, etc).

During and Immediately After the Avalanche

  1. Make sure the scene is safe. It is important that rescuers are not exposed to additional avalanche hazard. The actual avalanche path is usually safe if there isn't significant "hang fire" remaining above the slide.
  2. Once in a safe location (a.k.a. an "island of safety"), have everybody change their transceiver to either the off or search mode. If I had a nickel for every training that stumbled due to a transceiver being left in the transmit mode...
    Note that many transceivers can be set to automatically switch back to transmit mode. This can cause confusion if non-searchers change to search mode and then unknowingly return to transmit mode. It's usually best if non-searchers turn their beacons off after arriving at a safe zone.
  3. Determine the number of victims. The number of victims will influence how the search should be organized (e.g., whether you should perform a multiple burial search, when to call for additional help, etc). You can determine the number of victims by interviewing witnesses, using your transceiver, and by physical clues (e.g., finding two different brands of skis).
  4. Consider calling for additional help. When you should call for help is very situational dependent. Be sure to consider (1) how many additional minutes the victim will be buried if you do place the call, (2) how fast the rescuers can respond, and (3) how you will transport the victims once you do locate them.
    • If you are the sole rescuer, the several minutes it will take to call for help might be better spent searching.
    • If you have two or more searchers and one victim, having the second searcher call for help may save valuable time getting medical personal on scene.
    The decision to call for additional help is multifaceted and complex. It is best to consider these factors before an avalanche accident.
  5. Look for visual clues (e.g., gloves, skis, etc). If you see a glove or ski, check to see if it is connected to a victim. There are many examples, including avalanches that I have responded to, where gear on the snow surface (e.g., a glove) was still connected to the victim.

Signal Search

The goal of the "signal search" is to receive a signal. Period. If you switch your transceiver to search mode and receive a signal, you have already completed the signal search.
  1. With your transceiver set to search, move down the avalanche path until you obtain a signal. The appropriate width of your search path varies by beacon. The Pieps DSP Pro recommends 60 meters, the S1, Pieps DSP Sport, Pulse, and Tracker2 recommend 50 meters, the Ortovox 3+ and Tracker DTS recommend 40 meters, and the Freeride recommends 30 meters (learn more about recommended search strip widths). When in doubt, make narrower search strips! The few minutes you lose making narrower strips won't kill your friend; having to re-search the entire avalanche might.
    The following illustrations show the appropriate spacing for a 40 meter search strip width. Note that with a 40 meter search strip, you should get within 20 meters (half the search strip width) of the sides of the avalanche.
    Because it is much easier to move downhill than uphill and because you don't want to repeat the signal search, when in doubt, narrow your search strip width. It is always better to spend a few extra minutes searching a narrower strip than to end up at the bottom of the slide and have to repeat the signal search while hiking up hill. (Unfortunately, if the last skier in a group gets buried, the search must be done from the bottom.)
    When using a single-antenna transceiver, slowly rotate your beacon in all orientations (i.e., rotate your wrist 360) to increase the likelihood that your antennas will align with the victim's.
    Keep your gloves on. It's tempting to take them off and drop them in the snow when you are working with your transceiver, but you'll want them when probing, shoveling, and providing medical care.
    Remember, the goal of the signal search is to receive a signal. You should move quickly and deliberately. Locating the initial signal depends more on choosing an appropriate distance between search paths than on transceiver skill.

Coarse Search

The goal of the "coarse search" is to get within two or three meters of the victim. The coarse search technique varies depending on whether your avalanche transceiver has a direction indicator (i.e., has multiple antennas). These instructions only explain the directional indicator approach.

  1. Perform the signal search until you receive a signal.
  2. Follow the direction indicator (i.e., the arrow or lights). If the distance numbers increase, turn around and follow the direction indicator in the opposite direction. (The direction indicator can point in either direction on the flux lines shown in blue, below. You want to be moving closer to the victim. A few transceivers will tell you to turn around if you are moving away from the victim, but it's still important to look at the distance indicator. As you follow the direction indicator, slowly turn to re-orient the beacon so the arrow is pointed inline with the beacon.
  3. Continue to follow the direction indicator. It will follow the flux lines as it guides you to the victim in an arc as shown here.
    It is not unusual for transceivers to give an occasional "blip" in the wrong direction. Pause for a moment while holding the transceiver very still to allow the direction indicator to settle.
    If the indicator gives conflicting directions (e.g., left, right, left), choose one of the directions and begin walking. The direction indicator will resolve the conflict as you near the victim.
  4. Move relatively quickly while the distance is more than 10 meters. Remain calm and move deliberately. This is a bad time to fall and injure yourself.
  5. When the distance is less than 10 meters, slow down and pause for a few beeps each time the direction indicator changes direction.
  6. When you are within two or three meters, you have completed the coarse search.
    On most transceivers, the direction indicator will disappear when you are within two or three meters of the victim. If your transceiver continues to display the direction indicator, you should ignore it at this point and focus on the distance indicator as explained in the fine search.

Fine Search

The goal of the "fine search" is to get as close to the victim as possible so you can begin probing.

  1. Perform the coarse search until the distance indicator shows that you are within two or three meters of the victim.
  2. Only one rescuer is needed for the fine search. Additional rescuers should begin assembling their probes and shovels. If there are multiple victims, additional rescuers should begin a multiple burial search.
  3. Holding your transceiver just above the snow, slowly move it left/right and forward/backward while looking for the lowest distance.
    During the fine search, it is important that the transceiver always points in the same direction (i.e., don't let it rotate as you swing your arm to the side). Similarly, get on your knees and keep the transceiver very close (e.g., a few inches) above the snow.
    Continue to slowly move your hand from side-to-side looking for the lowest number, and then forward-and-backward while again looking for the lowest number. This "bracketing" approach helps you locate the strongest signal. You may find it helpful to put your foot on the spot with the lowest number and move it only when you find a lower number.
    Repeat this bracketing process until you find the spot on the snow with the lowest number (i.e., when moving the transceiver left/right or forward/backward causes the displayed distance to increase).
    (This promotional video shows how the Barryvox Pulse can help you perform the fine search "bracketing.")
    Don't waste a lot of time on the fine search. Performing one or two brackets in each direction should take less than 30 seconds.
  4. When you find the lowest distance, begin probing until you strike something, leave the probe in place and begin shoveling.
    If your transceiver has fewer than three-antennas, you may find more than one location on the snow that gives a low reading. These are spikes. If this occurs, simply bracket until you find a low reading (Step 3) and begin probing at that location. You may need to continue probing beyond the starting location, but you know you are very close to the victim and that you will find him if you use proper probing technique. (See the discussion of spikes for details on the distance and probing time.)
  5. If you have multiple victims, you will need to use special techniques to locate the additional victims.
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