Multiple Avalanche Burial Searches - Micro Search Strip Method

Yamnuska Mountain Adventures has adopted the micro search strip method for teaching multiple burial searches to students on our avalanche courses. The micro search strip method is a systematic search method used in avalanche multiple burial scenarios and works well for the wide variety of beacons that are available on the market today.

SET UP

Find a venue that is away from other people that might have beacons on and in a safe place. Don’t be tempted to use existing avalanche debris; stamp out an area 25 to 30m square to simulate avalanche debris.  Get two beacons, ensure they are transmitting, and then bury them wrapped in plastic bags at least 6m apart and no deeper than 50cm.  At this stage we want to perfect rather than confuse the system with beacons that are really close or very deep. This can come later when you have the basic system wired.  Put the beacons in the bottom of the hole and then place a target above it. This can be a plastic box lid or piece of plywood about 70cm by 50cm. The target simulates the victim when the probe is used. It also protects the beacon from over zealous probing and/or shoveling. Cover up the target with snow, stamp it down and then throw some more snow on top to hide it completely.

OVERVIEW

The search pattern will look like the image.  Strip widths are 3m to 4m wide. The search area is 25m to 30m square.

METHOD

Unlike an induction search, for the micro search strip to be effective it now becomes important to ignore the direction indicators and use the distance or audible signal only. The buried beacons are giving off numerous intersecting flux lines that are really difficult to follow using the induction method and often lead to searches just walking around in circles unsure of which signal to follow. Instead, think of using the beacon like a metal or mine detector and homing in on the target only when we get close to it.  You are now ready to start the micro search strip.

Beacons with a range/volume controls can be preset to a low setting and kept in the same orientation throughout the search (see table). You should carry a probe with you to locate the target as well as a marker for indicating where the first beacon was found. Proceed along one of the boundaries.  Strip widths are 3m to 4m wide. Comparing this distance to two ski lengths or two arm spans is a good visual clue for judging distances and keeps the strips more accurate. Try to keep the lines as straight and as parallel as possible.

Continue with the micro search strip until your beacons’ distance read-out, audio or lights indicate a burial nearby (see table).  You now proceed to a pinpoint search and the target is found using a systematic probing method.

We recommend the spiral or box probing system, with successive probes being 20 cm distance apart. This distance of 20cm is approximately a hand span from the tip of the thumb to the tip of the little finger, and gives another visual clue for accuracy.  When found, the target is marked, ideally by leaving the probe in. Ideally you should have two probes and leave one at the first strike as you continue looking for the second one. If you don’t have an extra probe mark this location with a ski pole, hat or glove. In a real rescue other searchers would now be coming in to shovel. In this exercise marking the location of the first beacon will help you avoid returning to that signal as you progress with the search.

Best of luck with your practice.  Questions?  Drop me an email.