OFF-SLOPE SAFETY EQUIPMENT

A few numbers to start with:

According to ANENA statistics, in the 2016-2017 season there were 68 avalanches with 13 fatalities.

While 80% of alpine hikers are now equipped with DVAs, only 45% of off-piste skiers and snowboarders are equipped.

With the cell phone network that covers the majority of ski areas, we feel safer to call for help, but statistics show that the chances of survival decrease rapidly with time. Only rescue services organized directly by the people on the spot and equipped guarantee a very high percentage of survival.

It all comes down to the first 15 minutes:

Between zero and 15 minutes of burial :

The chance of survival is 91%.

The majority of victims are fatally injured when falling into the avalanche.

From 15 to 45 minutes of burial :

The chance of survival drops to 25%.

This is the asphyxiation phase. Without an air pocket, with a compressed chest the victims die of asphyxiation.

After 45 minutes of burial :

The chances of survival decrease gradually depending on the presence or absence of air. Beyond 2 hours, the chances of survival are only 7%.

The importance of the material :
For a quick rescue you need:

Locate the victim with the DVA and a probe.

The professional rescuers in addition to the dogs have specific tools such as the RECCO system which certain equipment and clothing are equipped.

Gain access to the victim.

With only skis and hands it can take more than an hour to dig 1 m into avalanche snow. That’s why it’s important to have a shovel on you.

The DVA

What is a DVA or ARVA?

The Avalanche Victim Detection device is an electromagnetic transceiver operating on the standard frequency of 457kHz. A DVA has two functions: transmission and reception.

When going off-piste, the DVA must be in the transmitter position “on” permanently (after having checked the correct operation of the device).

In case of an avalanche, the witnesses present switch their DVA to “receive mode” to locate the victims.

The choice of his DVA will be taken into account:

Signal range and bandwidth:

The greater the bandwidthis , the earlier the victim can be located.

Digital and analogue modes.

Until 1998, manufacturers used analogue technology. In this case, the signal from the transmitting DVA is converted by the receiver into sound waves. When a receiving DVA picks up a transmitting DVA, it emits a “beep” that is as louder as the two devices are closed to each other or the more correctly oriented they are in relation to each other. A potentiometer allows you to vary the sound intensity of the signal by adjusting the sensitivity of the receiver. All DVAs manufactured before 1998 are analogue.

In 1998, a second generation of DVAs appeared, using digital technology exclusively or in combination with analogue technology. This is referred as digital DVA. The transmitter signal is analysed by a microprocessor which converts it into two types of visual indications:

• a progress indication (numerical value appearing on a screen) 
• a direction indication (diode or arrow that lights up when the DVA being received is correctly oriented in relation to the device being transmitted).

The number of antennas:

Arva’s consist of 1 to 3 antennas. New models all have 3 antennas which simplify the search for victims by providing distance and direction information. They are also much more precise in the final search.

Other functions:

Analysis and separation of signals in case of burial, multiple marking of victims, protection function for rescuers with automatic activation of the transmission mode without movement for a certain time (over avalanche).

Simple rules for using DVAs :

• To be efficient with a DVA you have to know how to use it in search mode. You don’t have to wait for the accident to learn because with the stress and confusion, the search must be like a reflex. Practice your search with DVA before the accident.
• Do not wear your DVA just under your jacket: as soon as it gets warmer, when you take off your jacket the dva appears in the open air: in case of an avalanche it could be torn off!
• Do not leave without a snow shovel or a probe : you have just found a person buried in less than 5 minutes but you need 45 minutes to free them by hand… the time it takes to die asphyxiated under the snow.
• Do not leave with very worn batteries (or without batteries at the beginning of the season).
• Knowing how to give up a race, the DVA is not an avalanche “shield”, nor a guarantee of survival …
• Check that all the equipment is in good working order and that it is switched on.

The use of a DVA must be associated with a probe and shovel.

The average search time for a victim is estimated at:

11 mm with a DVA, probe and shovel.

25 mm with a DVA and a shovel

An hour with a single DVA.

When you know that everything is played out in the first 15 minutes, it is imperative to go into the mountains with these 3 elements of security.

The probes

They are made of aluminium for strength or carbon to save weight.

Their length must be at least 2 m. The standard length is 2.4 m, with rescuers using 2.80 to 3.2 m probes for greater sounding capacity.

Shovels

Shovels (handle + bucket) can be made up of combinations of the following three components: Carbon, aluminium and polycarbonate. Carbon and polycarbonate will be lighter but aluminium will be more efficient on hard snow.

Telescopic handles help to make the shovel more compact for storage but also more efficient once deployed for shovelling.

Some models also have a ｫ pickaxe ｻ position for more efficient clearing.

 

Airbags

The airbag is an important additional safety feature. Contrary to popular belief, it does not completely eliminate the risk of death but halves it.

Out of every 100 avalanche victims 22 perish. This number is reduced to 11 with a successful airbag activation.

However, according to ANENA, it is very important to become familiar with the triggering process. 20% of all inflatings fail and 60% are due to the fault of the user.

On the other hand, the personal safety benefits of airbags are quickly negated if users use them to justify increased exposure in terrain where larger avalanches are possible.