BACKUP SEARCH TECHNIQUESNo two avalanche rescue scenarios are the same.
Throw in more than two buried victims–all close
together–and a search can get complicated,
requiring special searching techniques. While mosttransceivers on the market come standard withmultiple search functions such as “marking,” these
are not 100 percent reliable, due to a phenomenon
called “signal overlap” (see www.backcountryaccess.
com/research). Therefore, it is important for rescuers
to be well trained in more than one method forsolving multiple burials. With any transceiver, asearcher may need to utilize special multiple searchtechniques to rescue the victims, especially if there
are more than two victims within range.
It’s important to note that most multiple burials canbe approached as a series of single burials, solved
either “in series” or “in parallel” using normal searchmode. The only time multiple burials can become
truly complex is when the victims are in close
proximity (≤ 10 m) to each other.
In general, we recommend using Signal Suppression(Tracker3) or Special mode (Tracker2/DTS) for all
scenarios involving only two victims. When more than
two victims are buried, then special techniques might
be necessary–especially if some of the victims are inclose proximity.
Remember: it’s fun to go out and practice multiple
burial searching, and we encourage you to master it!
But manpower, group organization, and excavation
efficiency play equally important roles in real-life
avalanche rescues.

The following section highlights two multipleburial search techniques that serious
backcountry travelers and guides should know.

THREE CIRCLE METHOD:
Most effective in large, flat areas

The three circle method is used with yourtransceiver in standard search mode. It is mosteffective in large, flat areas, as it will cover only aportion of the debris pile and sometimes requires
walking uphill of the victim.
Figure A

Search (SE) mode
In search mode (SE), only thestrongest signal (transceiver #1)
is shown. Signals further away
are received (transceiver #2), but
not shown in the distance anddirection display.

To perform this method, stay in SE mode and takethree steps away from the first found victim. With
your searching transceiver on the snow surface,walk in a circle of this radius around the victim,
attempting to acquire another signal in SE mode. If a
new signal is acquired, begin bracketing until it has
been pinpointed. For this method to be successful
the searcher should rely on the distance readings andignore the directional arrows. Maintaining orientationof the searching transceiver is unimportant, as thegoal is to lose the strongest signal and capture thenext strongest signal as soon as possible.
If no other signal is captured, take another threesteps back and repeat up to a maximum of threecircles (nine steps). If a new signal is acquired andpinpointed, and there are still more victims suspected
to be in close proximity, then return to the point
where you abandoned the circle search (in SE mode)and begin searching again from there.

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Figure B

Figure C

When using the threecircle method, walk aroundtransceiver #1 in concentric
circles until you detect thesignal of transceiver #2.
During the first circle, keep
the searching beacon as
close as possible to thesnow surface.

Consider moving to micro
search strips if the searcharea is small and the close
proximity brackets areilluminated.

MICRO SEARCH STRIPMETHOD: Most effective in complex

multiple burials in a smaller search area
This method allows a searcher to use a simple,
systematic approach to solve a multiple burial. Itworks well in small scenarios (such as guiding exams)
since it involves making many tight passes throughthe debris pile. It also works well in steep debris
since it doesn’t require walking uphill.
Based on the number of buried victims, you will
determine how wide your search strips need to be(this is usually an estimate as you’re “thinking on thefly”). The width of your search strip will decrease as
the number of victims increases. If the Tracker2 orTracker3’s close proximity brackets are illuminated,
we suggest using 3-meter search strip widths.
Like the three circle method, this technique is usedwith your transceiver in standard search mode. The
searcher must rely on the distance readings on thesearching transceiver, not the directional arrows. Thisis because it requires bracketing rather than following
the flux lines.
If no signal or only one signal is detected, follow yournormal 40-meter search strip widths. If more than one
signal is detected and the close proximity lights turnon, reduce your search strip widths to 3 meters.
Remember, these techniques all assume there is only
one searcher available. With additional searchers you
would spread out and search “in parallel”(see www.backcountryaccess.com/research).

Do not leave your microsearch strips and start
bracketing until you see
distance readings that areless than or equal to yoursearch strip width (in thiscase, 3 meters). When
this occurs, find the lowest
distance reading and begin
probing.
Remember to search as
close as possible to thesnow surface. Always markthe point at which you
departed from your search
strips and return to thatpoint to resume searchingfor the next signal.

3 metersȝm ȝm40 meters

Micro Search Strips

Three Circle Method

HOW TO PASS A GUIDING
EXAM USING
TRACKER3/2/DTS
After 20 years of transceiver searching with theworld’s top rescue personnel, we have found thatstrong searchers rely on a multitude of techniques.
A complex transceiver search may require a searcher
to act on the fly and improvise based on how thescenario unfolds, often combining two or threetechniques. There are a few methods you shouldhave ready to go (micro search strips, three circle
method, Special mode (SP), Signal Suppression(SS), Big Picture (BP), etc.). Variables such as thenumber of victims, the distance between them, andthe victim’s burial depth make it nearly impossible toadvise one technique over another.
The following hybrid technique is targeted directlyat those striving to pass a guiding exam and foradvanced users looking to round out their searchskills. While no two exams are the same, they all
share similar characteristics:

• There is only one transceiver searcher (yourself).
• All transmitters are buried in an area of		 100 m x 100 m or less.
• You can usually count on two transmitters within		 close proximity of each other and a third spaced		 20 m or more away.
• Out of the 3 transmitters, 1-2 may be buried over		 2 m deep.
• Finally, in most guiding exams you’re not allowed		 to turn off transmitters once they’re found.
The key to an effective multiple burial search withmore than two victims is to eliminate terrain. It isessential to be 100 percent sure which areas you’ve
searched and which areas you haven’t. The best
way to do this is to follow a disciplined signal searchthrough the entire deposition area, only departingfrom that pattern to perform a fine search at close
range. Once that victim is pinpointed, always comeback to the point where the pattern was abandoned,
then resume the signal search from there.
If the scenario is small enough, don’t be afraid tobegin micro search strips immediately or at least cut
your 40 m search strips down to 20 m. Generally,
when you enter the search area, be sure not to move
too far down the slope, as it’s always inefficient totravel back uphill. Sometimes one transmitter isintentionally tucked up high on the flanks and can beeasy to miss, especially if this transmitter has poortransmit strength or antenna orientation.
If a signal is immediately received, but is greater than
20 m away, continue your signal search. Be sure to get
within 20 m of each flank and cover the entire path. Do
not abandon your disciplined signal search until you
obtain a reading lower than 20 m. This will prevent you
from missing a weak or poorly oriented transmitter.
Once you commit to transmitter #1, mark the spot
where you abandoned your signal search. Then
conduct the coarse and fine searches, and probe.
Locate the first transmitter and take a moment togather additional information: If the multiple burial
icon is illuminated, be prepared to use Signal
Suppression, SP mode, or micro search strips,
especially if the close proximity brackets are also
illuminated. However, since multiple-burial andclose-proximity lights are not 100 percent reliable(due to signal overlap and/or electromagnetic

3noise), we suggest going into Big Picture or SPmode after pinpointing each victim, to clearly
determine if another one is nearby. If no othertransmitters are within 20 m, continue with yoursearch strips, but remember to return to the point
where you abandoned the signal search. This will
ensure that you leave no areas unchecked uphill of
the found victim.

If another signal of 20 m or less is displayed in Big
Picture or SP mode, then suppress the found signal(if you have Tracker3) and pinpoint the second victim(with T2 or DTS, pinpoint using Search mode). While
this will pull you off your disciplined signal searchpattern, it will ensure that excavation can begin assoon as possible.
Similar to before, enter Big Picture or SP to see if
any other signals are within 20 m. If so, suppress thefound signal and pinpoint the next one. If not, return
to your signal search pattern. Repeat this processuntil all victims have been located and excavated.
Figure DHybrid method using micro search strips and BP/SS modes

If the next signal in
BP mode reads lessthan 20 m, suppress
the found signal andgo straight to thenext one.
If the signal in BP
reads greater than
20 m, then go backto the point where
you abandoned yoursignal search, andresume your signal
search from there, inSearch mode.
In this case, therescuer suppressed
victim #1’s signal andwent directly to victim#2. Victims 3 and 4
were both more than
20 m away, so thesearcher returnedto the signal searchpattern instead ofsuppressing.
Make sure that you
always identify thepoint ( ) where you
abandon your signalsearch.

SESESESESSBPBP

#1

SE

#2

SEBP
#3

SE

#4

While no two scenarios are the same, the abovetechniques will provide you with a solid framework towork through any complex scenario. Remember thattransceiver searching is the fast part. Most multiple
burial rescues are limited by the number of shovelers
available. However, special techniques may bebeneficial if there are enough rescuers available forshoveling.
These techniques are mainly used and directed
toward professional guides and advanced searchers.
Shoveling is the ultimate crux in an avalanche rescue
and the efficiency of your rescue will greatly dependon how many resources you have to dedicate toward
excavation. Be sure to check out BCA’s video on the“ABC’s and D of Digging” at
www.backcountryaccess.com/education.
To learn more about advanced search techniques or
to set up a “How to pass a guiding exam” training
session, please contact info@backcountryaccess.com.

Backcountry Access, Inc.
Boulder, Colorado USA
www.backcountryaccess.com

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