Avalanche Risk Factor

Search and Rescue

You are the rescue team

95% of survivors are rescued by their companions.

Before the Tour

Ensure that everyone has had practice searching with transceivers. It might be you who will be buried…

Do not assume that others are more competent and don’t need practice. Do not assume that you do not need practice.

Appoint possible search leaders.

Stress the need for discipline.

Make sure everyone knows the plan for the tour and the reasons for the route chosen. They might need to find their own way out.

During the Avalanche

Observe avalanche and positions of victims in avalanche. Note last seen positions with reference to landmarks (eg rocks, trees). This eliminates a whole section of the slope from the search. Spot clothing, equipment, body parts sticking out of the snow. Equipment, skis etc may or may not indicate victim’s position.

After the Avalanche stops

  • Take charge. How many are missing? Count heads. Roll call.
  • Appoint searcher(s) to find victims.
  • Appoint resuers to dig out and attend to victims.
  • Appoint guard(s) to watch for further avalanches.
  • People not involved in search to stay high in a safe region and keep their skis on.
  • Determine safe way out of area.
  • Switch transceivers to SEARCH. For most people, search is easier and faster with a digital transceiver.
  • Switch off mobile phones to prevent them interfering with the search.

BEWARE OF SUBSEQUENT AVALANCHES. Whilst transceivers are switched off or to Search, there is a high risk that if someone is buried by a subsequent avalanche they will not be found in time. Guards must shout warning if subsequent avalanche occurs. Transceivers need to be switched back to TRANSMIT quickly.

Search

Every search has four phases:

  • SIGNAL SEARCH – to find the signal from the victim’s transceivers
  • COARSE SEARCH – to come within 3 metres of the victim
  • FINE SEARCH – to find the victim’s precise position.
  • PINPOINT PROBING – to find the victim’s exact depth of burial and mark their position.

Control the search. Keep it progressing but not rushed. Digital transceiver searches tend to be easier.
Searcher(s) start ski traverse and zig-zag search down path of avalanche downwards from level of party. If avalanche is large it may be more appropriate for two or more searchers to make parallel searches.

When signal(s) received, home in on the nearest (strongest) signal.

PRACTICE IN SEARCHING IS ESSENTIAL particularly for multiple burials.

Be disciplined. It may be better for just one person to do the search in a disciplined way than for everyone to rush in, some with transceivers still transmitting, and getting in everyone else’s way. If more than one person is searching, a separate person should direct and control the search.

LOOK OUT FOR VISUAL CLUES – AN ARM WAVING IN THE SNOW, JACKET, RUCKSACK, SKIS, AVALANCHE BALL.

This description refers to the use of Tracker2 transceivers for illustration. Other transceivers can be used in a similar way but the operation of each may differ in detail from the Tracker2. Always refer to the manufacturer’s instructions on use.

search phases

Search phases

SIGNAL SEARCH – Switch all transceivers to SEARCH mode. If the victim is more than 40m from you the Tracker2 will be silent. Using the Tracker2, sweep search from side to side down the track of the avalanche – traverses and kick turns – with the line of each traverse ending no more than 40m (20m for other transceivers—check user manual) from the previous line, until the Tracker2 starts to beep. Turn no more than 20m (10m for others—check user manual) from the edge of the avalanche track. Do this quickly without stopping but do not rush. If there is more than one victim, continue the Signal Search even after the first contact in order to discover other victims who may be near the other side of the avalanche and to avoid having to search uphill later.

COARSE SEARCH – When the Tracker2 starts to BEEP, you will be about 40m from the nearest victim. The range display shows how far you are away along the curved field lines from the target transceiver. The indicator lights of the Tracker2 point towards the victim along the field lines. If there is more than one victim to be found continue the Signal Search. If more than one victim has been detected, the multiple burial indicator lights up and the Tracker2 may indicate their directions more or less alternately depending on how fast each target transceiver sends its “beep”. Do not rush this. Transceivers “beep” at roughly 1 second intervals and the receiving transceiver can only display one at a time, so it is better to take your time in order to identify the victim positions accurately.

Follow the direction indicated by the lights to the nearest victim keeping the central light pointing to the victim. This might not be a straight line. As you come closer it locks to the strongest signal so only one victim will be indicated. If you are descending this should be the highest victim on the slope.

If weaker, more distant signal(s) are lost (the Tracker2 has locked to the strongest signal), mark the point (the Split Point) so you can return there later if necessary to resume the search. The line followed will curve since the Tracker2 follows the field lines of the victim’s transceiver. With a Tracker2, as you get closer, you will hear the beeps become frequent, until a rapid beeping indicates you are very close. Make sure that the range indicated is always getting smaller and is not increasing again.

FINE SEARCH – At about 3 metres from the victim, Stop, and do a grid search carefully with the Tracker2 close to the snow surface, preferably from below, facing uphill. The victim’s face might be buried below your feet so tread carefully. At 2 metres range, the Tracker2 direction lamps switch off automatically and only the range and audible ‘beep’ operate.

GRID SEARCH – Keeping the Tracker2 level, close to the snow, and always pointing in the same direction, move it with your hand in a grid-wise search, forward and back, side to side. As you overshoot, the range will start to increase so reverse the movement until a minimum is reached in both directions—forward-back, side-to-side. Mark this position in the snow.

DO NOT TRAMPLE ON THE VICTIM’S AIRSPACE

PINPOINT PROBING – At this minimum, probe the snow at right-angles to the snow surface at 25cm (10″) intervals in concentric circles until contact is made. Leave the probe in position to mark the victim. The probe will tell you the depth of the burial.

MULTIPLE BURIALS – If more than one signal is detected the Tracker2 may indicate both of them alternately and the multiple burial indicator lights up. If the victims are close together, the multiple-burial indicator flashes. Only the closest victim will be indicated unless you happen to be halfway between them.

multiple burials

Multiple burials

Having found the first victim, if there are more victims buried and if you can’t turn off the transmitter just found yet, you can still find other victims by using the three circle search method to locate nearby victims.

If others are available to dig, the lead searcher should continue the search whilst excavation of the first victim is proceeding.

The Three Circle Method to find closely buried victims, searches in 3 concentric circles around the victim just found (this method works for all types of transceiver):

  • Step 3 big steps to the side (3 metres or the length of an avalanche probe) from the victim already found. You can use the Tracker2’s display to confirm your distance from the victim.
  • Search in a circle of radius 3m round the victim already found, slowly scanning the transceiver across the slope as you search. Somewhere halfway between the first and the next victim the Tracker2 may indicate both signals alternately and you can find the next victim. At this point it may help to move the transceiver with your hand towards the original victim and then in the opposite direction to confirm that a second signal has been detected. Go to the second victim. The Tracker2 will lock to the new signal when it becomes the strongest signal.
  • If no victim is found on this search increase the circle radius to 6 metres, again using the display to confirm distance, and repeat the search.
  • Should no victim be found again, increase the circle radius to 9 metres and repeat the search. The diameter of this circle (18 metres) approximates to the 20 metre search track interval used on the initial search.
  • Fine search and Pinpoint Probe to locate the victim as before.

Should the Three Circle Search fail, or if there are more victims to be found, start a new Signal Search to find remaining victims. You may have to return to the Split Point in order to do this. Not all avalanches are simple plate slides. Frequently the path of the avalanche splits and victims can be carried to quite different positions thus complicating the search. Victims can be buried under the edge of the slide path, behind rocks, or in hollows.

Digging

Shovelling out a huge quantity of compacted snow to free an avalanche victim is time-consuming and extremely tiring. Digging a hole in compacted snow using only skis and ice axe is impossible so all members of a party must carry a lightweight metal snow shovel. Plastic shovels are unable to cut through the ice and concrete-snow of avalanches efficiently. Even with a team of practiced rescuers it can take more than 10 minutes to dig out a victim buried two and a half meters under the surface.

Digging is very tiring. Change the diggers frequently to allow them to rest between digs. If you are alone it might be better to leave a deep burial in favour of finding a shallowly buried victim who might then be able to help dig out the deep burial.

Keep your transceiver attached to your body. DO NOT LAY IT ON THE SNOW. Use it to confirm position of victim frequently.

Leave the probe in position to mark the position of the victim.

DO NOT TRAMPLE ON THE VICTIM’S AIRSPACE

Dig on your knees on the downhill side and dig towards the probe.

Start digging 1.5 times the burial depth away, 2m wide. This will allow space to roll victim onto side (recovery position) or onto back for artificial respiration.

Throw snow to side. When waist deep throw snow downhill.

If two diggers, start digging side by side and throw snow to side. Later, one behind the other, the uphill person throwing snow downhill for the other to clear. Change over frequently.

Dig in relays. As soon as a person tires, replace him/her. Change over frequently.

Slice the snow into blocks, don’t try to lever it out as the handle of your shovel may break making it useless.

If deep burial, dig tiers. Diggers on each tier remove snow dug from lower tiers. Deep burial rescues are slow.

Clear space round face and chest first.

Clear snow from mouth and airway.

Resuscitate (mouth to mouth) if necessary.

If further search proceeding turn off victim’s transceiver.

Extract victim as quickly as possible.

Keep victim warm. Space blanket. Multi-person bivouac shelter.

Dig out victims that are close to surface first. It’s better to have one survivor than two corpses.

Avalanche Risk Factor