Avalanche Basics

Avalanche Search and Rescue

The first 20 minutes are critical when rescuing someone buried in an avalanche. Chances of survival are still around 85% – afterwards these chances decrease drastically. On the other hand, the search for and rescue of a single avalanche victim takes 20 minutes on average. With this in mind, it is clear how precious time is and how invaluable a good training with his avalanche rescue gear can be.

Avalanche rescue is a race against time! Companion rescue, therefore, provides the greatest chances of survival for a buried subject. Companion rescue means that buried subjects are located and excavated by members of their party immediately after the avalanche slide.

If an avalanche occurs

As a Victim:

  • Escape to the side
  • Discard skis, snowboards, and poles (anchor effect)
  • Try to stay on top
  • Close your mouth; place your hands in front of your face (clear airway when the avalanche stops)

As a Witness:

  • Memorize the last seen point as well as the direction of the avalanche
  • Fix the primary search strip

Emergency plan

The emergency plan lists the basic actions to be taken for a successful companion rescue operation:

  • Obtain an overview
  • I am searching with a transceiver: SEARCH
  • I am not searching: Activate rescue-SEND (PULSE Barryvox only)
  • At least one rescuer carries out an immediate search using their eyes, ears and a transceiver
  • Transceiver search complete: Switch all transceivers to SEND
  • Locate buried subject – provide first aid – Raise the alarm

Searching for buried subjects

Standard procedure for newer transceivers with direction arrow:

  1. Signal search: Search area to the point where the first signal can be detected.
  2. Coarse Search: Search area starting from the reception of the first signal until the immediate vicinity of the buried subject. In this phase the signal search pattern is abandoned in order to follow the signals leading to the buried subject.
  3. Fine Search: Search area in the immediate vicinity of the buried subject.
  4. Pinpointing: First use of the probe until probe hit.
  5. Multiple buried subjects:Pattern recognition is used to record buried subjects in a list and mark them as found by means of a marking function. Pattern recognition and the marking function help to locate most buried subjects without having to use any special procedures (search methods) for multiple burial situations.

Signal search

During the primary search, the avalanche surface is searched systematically with the search strip width of your device (distance depending on type of device) until you pick up a signal. The objective of the primary search phase is to detect a signal.

To optimize the range, rotate the transceiver around all axes. Once a signal is received, maintain the device orientation and continue walking until the signal can be heard clearly. The primary search phase is concluded.

Coarse Search

Hold the transceiver horizontally in front of you and proceed in the direction indicated by the arrow. If the distance increases, you are moving away from the victim. Continue the search in the opposite direction. The transceiver will lead you to the buried subject quickly and reliably.

Do not move backwards, otherwise the direction indication will be incorrect.

Fine search

At this point, you must hold the transceiver just above the snow surface and determine the point with the smallest distance reading by bracketing.

Device with a marking function: Don’t mark the location of a buried subject until the location has been confirmed using a probe pole!

Triage

With limited resources (few rescuers) it is not possible to locate and dig out all the buried subjects at the same time. The question arises in which order the buried subjects shall be rescued. Subjects with higher chances of survival should be located and dug out first. Besides simple terrain factors, e.g. drop over a cliff, the burial depth and by the PULSE Barryvox® vital data are an important triage criteria.

Probe

Pinpointing the location of a buried subject is not possible with a transceiver alone. The burial depth and the orientation of the subject can be determined easily and quickly with a probe pole. Starting at the point with the lowest distance reading or loudest tone, apply a spiral search pattern. Always probe at a right angle to the snow surface.If the buried subject is hit with the probe pole, the pole is left in the snow. It serves as a guide while excavating the buried subject. The burial depth is also a triage criterion. In situations with limited resources deep burials are located later.

Excavating the Buried Subject

Size the area to be dug out generously. Pay attention to the presence of an air pocket and avoid trampling on top of the buried subject. Access the buried subject laterally. Digging must be practiced as well. It takes by far the most time.Cut out blocks of snow with the shovel. The lead shoveler of the group should be relieved from time to time. Rotating clockwise at given intervals is easiest.

First Aid

Patient assessment, ABCs

  • A Airway - Clear the airway (snow?)
  • B Breathing - Perform rescue breathing as necessary
  • C Circulation - Perform CPR as necessary

Basic Life Support

  • Depending on ABCs, continue rescue breaths or CPR on patient
  • Prevent further heat loss
  • If patient is responsive and can control his/her airway, administer warm fluids
  • Handle patient very gently
  • Evacuate by helicopter whenever possible

Notification

It is not possible to provide a complete list of all mountain and helicopter rescue services in this manual. Please inform yourself prior to your trip about the local rescue services and their phone numbers and radio frequencies.

Message of accident

  • Who – is calling?
  • What – happened?
  • Where – is the accident site?
  • When – did it happen?
  • How many – casualties (nature of injuries)/how many rescuers?
  • Weather – at the accident site?

Alpine emergency signal

If you cannot call for help using a radio or phone, you should try to communicate the emergency using thealpine distress signal:

Tour Planning

We would like to provide you with some basics on this complex topic and recommend thorough initial and ongoing advanced avalanche training.

Most winter outdoor travelers trigger their own avalanches. The snowpack is fragile. Slab avalanches resemble set traps: If we trigger it, the trap snaps. Remember that a small slab of 100 m3 weighs about 25 tons!

The planning of the next tour should start days before the actual start, following question must be asked:

  • What is the current danger level?
  • What is the steepest slope angle?
  • What is the slope exposition?
  • Is all the emergency equipment available and ready?
  • What is the weather forecast?
  • How large is the group and what are the individual skill levels?

Danger LevelSnowpackTypical IndicationsTours

1 - Low

Snowpack generally well bondedNoneGenerally favorable conditions
2 - ModerateOn some steep slopes snowpack only moderately bondedDifficult to recognize, no alarm signalsGenerally favorable conditions, careful choice of route on steep slopes of aspect and altitude as given in the avalanche forecast

3 - Considerable

On many steep slopes medium to poor snowpack, bonding only"Whumping" noises, some spontaneous avalanches, Remote triggering at the foot of the slopesPartly unfavorable conditions, experience in assessing avalanche risk required, wherever possible avoid steep slopes of aspect and altitude as given in the avalanche forecast
4 - HighPoor bonding of snowpack on most steep slopesSpontaneous avalanches, remote triggeringUnfavorable conditions, tours only in moderately steep terrain < 30°, be aware of avalanche runout zones
5 - ExtremeGenerally poor bonding of snowpack, mostly unstableSpontaneous avalanches and remote triggering on a large scaleVery unfavorable conditions, refrain from tours
Slope exposition and slope angle

The following areas must be taken into consideration:

  • Low danger: the immediate vicinity of the track
  • Moderate danger: 20m to the left and right of the track
  • Considerable danger: the entire slope

Adequate spacing is an effective method to minimize stress on the snowpack. Ascending, the spacing should be approximately 10 meters; descending approximately 30 – 50 meters, due to the additional stress. Danger zones should be traveled one person at a time. Minimize the stress on the snowpack by making long turns.

Group Check

Before a party takes off, the transceivers of all the party members must be checked. To conduct this test, the function group check or Search mode is activated on a single transceiver within the party. Make sure all the other transceivers of the party are in SEND mode. The test is successful if all the members of the party can clearly hear beeps within the range indicated on the display. The members of the party must be spread out appropriately to avoid mutual interference. If the individuals are too close to each other, the group check’s results become increasingly unreliable. If no tone is heard within the indicated range, the device may not be used, and the device or its batteries must be inspected further, as needed.

The following standard safety precautions should always be taken regardless of the danger level:

  • Avalanche transceiver on SEND, along with a probe pole and shovel
  • Avoid fresh wind-deposited snow
  • Consider daily fluctuations in temperature, especially in the spring
  • Constantly assess the conditions throughout the trip

Risk Assessment

With the following amounts of new snowfall within 1–3 days, the danger level is at least considerable:

  • 10–20 cm with adverse conditions
  • 20–30 cm with average conditions
  • 30–50 cm with favorable conditions

Adverse conditions:

  • Strong wind (> 50 km/h)
  • Low temperatures (< -8° C)
  • Slope seldom traveled

Favorable conditions:

  • Light wind
  • Temperatures little below 0° C
  • Slope traveled frequently

Danger level
Skiable / ridable slope angle
2 - Moderateless than 40 degree
3 - Considerable

less than 35 degree

4 - High
less than 30 degree

Untracked steep slopes (> 30 degrees)?
Spacing of at least 10 m.

Outside of the forecasted aspect or altitude ranges?
The danger level is generally one level lower.

At the edge of the forecasted aspect or altitude ranges?
Do not approach the limits

Avalanche Forecast Centers
It is impossible to publish a list of all the avalanche forecast centers in this user manual. Current information about all the avalanche forecast centers worldwide can be found at the CyberSpace Avalanche Center website at http://www.csac.org