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EquipmentCheck | Avalanche-Airbag-Backpacks

What are the specs behind the different systems?

by Teja Stüwe • 01/09/2025

The danger of avalanches accompanies us winter sports enthusiasts, but modern equipment such as avalanche airbag backpacks can significantly improve the chances of survival in an emergency. Various scientific studies have investigated how effective avalanche airbags actually are. In a study on the effectiveness of avalanche airbags by Haegeli et al. (2014)[1], it was found that an inflated airbag can prevent around half of all fatalities in avalanche victims caught in an avalanche of size 2 or larger. The non-deployment rate found is 20% and is therefore the limiting factor of the airbag.

The basics

Avalanche airbags utilise the so-called paranut effect (also known as the muesli effect): When a mixture is shaken, larger particles, such as Brazil nuts, rise to the top, while smaller ones, such as peanuts, slide to the bottom. Simply explained, the small particles fall into the gaps between the larger particles as soon as the mixture is shaken or moved. This effect is easy to observe - yet the exact physical background remain a mystery that still puzzles scientists to this day. Avalanche airbag backpacks utilise precisely this effect. By inflating, you increase your own volume and thus the probability of remaining on the surface of the avalanche. However, when wearing an avalanche airbag, you should be aware that this effect may not work in certain situations and therefore does not increase your chances of survival. You can put yourself in the position of a Brazil nut and briefly consider whether you now have an advantage over the "peanuts" or not. Examples of such situations in which the airbag offers no advantage are terrain traps, such as deep holes or ditches. An airbag backpack does not help in such cases, as the terrain collects the snow in depressions or behind obstacles. As a result, the wearer can be buried or trapped despite the buoyancy. Another example is wet snow avalanches: Here the greatest danger is not so much being buried, but the force of the avalanche, which can cause serious mechanical injuries, broken bones or internal injuries.

There are different types of airbag balloons. Most systems use a mono airbag, which differs in volume depending on the model. However, dual-chamber systems have now also been developed. ABS has introduced the so-called TwinBag, in which two separate airbag balloons are inflated. The Arva Reactor also has a double airbag system with two separate chambers. If one of the airbags is damaged, the other continues to provide protection. Mammut has developed the so-called Protection Airbag System which protects the head area and thus offers additional trauma protection to prevent blunt injuries.

Avalanche airbag systems can also be divided into mechanical and electronic systems. Mechanical systems are further divided into gas pressure and air pressure systems. In the case of electronic systems, a distinction is made between battery and supercapacitor-operated systems. The basic physical principles of these systems are decisive for the advantages and disadvantages based on them, so it is worth taking a look behind the scenes.

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Components of a mechanical Airbag System (by Mammut)

Mechanical systems

Mechanical avalanche airbags are characterised by their ease of use, as they do not need to be switched on. They consist of a manual trigger that is activated by pulling a handle. Either mechanical or pyrotechnical activation opens the gas cartridge and the compressed gas (air, nitrogen, argon or carbon dioxide) then flows into the airbag and inflates it.

In mechanical deployment systems, the airbag is activated by a handle with a wire pull system: A pull on the release handle tensions a cable that triggers a spring. This drives a needle that punctures the cartridge, releasing the gas that fills the airbag.

With pyrotechnic triggering, the handle contains an explosive device that triggers a tiny explosion when pulled. A metal pin, which is pushed by the explosive device, finally punctures the cartridge and the gas escapes. After such a triggering, both the cartridge and the trigger handle must be replaced. Pyrotechnic trigger mechanisms are now only used in ABS avalanche backpacks.

In addition to the cartridge, most mechanical airbag systems also have a venturi nozzle, which draws in additional air from outside when the airbag is deployed. The Venturi effect occurs when the speed of the gas increases during a constriction, causing the pressure to drop. This can be described using Bernoulli's equation. Due to this lower pressure, air is drawn in from outside. Approximately one third of the inflated airbag consists of the gas in the cartridge, while two thirds are filled with ambient air.

The cartridges usually have a pressure of between 200 and 300 bar and are made of aluminium, steel or carbon, depending on the manufacturer. Some manufacturers even offer both a more expensive, lighter cartridge made of carbon and a cheaper, heavier version made of steel or aluminium. But what is the difference between air pressure, compressed nitrogen, argon or carbon dioxide systems? Air pressure systems are the simplest and therefore the cheapest to refill. Most pressurised gas cartridges, on the other hand, have to be completely replaced or refilled by the manufacturer. Apart from this, air pressure systems are functionally identical to pressurised gas systems. With regard to the choice of gas in the cartridge, the question arises as to how the chances of survival are reduced in the event of a burial if the airbag is deployed but then damaged. In a breathing cavity, you could then inhale either normal air or a gas such as carbon dioxide, nitrogen or argon - gases that can reduce the oxygen content. In such circumstances, pressurised air systems may offer an advantage over pressurised gas systems. Among pressurised gas systems, carbon dioxide systems have another special feature: carbon dioxide, unlike other gases, is in liquid form at elevated pressure. This saves significantly on volume, allowing smaller cartridges to be used - a clear advantage in terms of pack size and weight. In carbon dioxide-based systems, the carbon dioxide can partially freeze under cold conditions during rapid decompression. This causes dry ice to settle in the cartridge, which can hinder the inflation process. The Alpride 2.0 system is the only one on the market that uses carbon dioxide. However, this problem has been solved by combining carbon dioxide with argon - a gas that is less likely to freeze. This means that the airbag remains reliably functional even at low temperatures.

The pressure cartridges of mechanical avalanche airbags are classified as dangerous goods when travelling by air. According to IATA (International Air Transport Association) guidelines, one avalanche airbag backpack with cartridge per person may be transported on an aircraft. The backpack must be packed in such a way as to prevent unintentional deployment and the airbags must be fitted with pressure relief valves. In some cases, prior notification is also required. An exception applies to flights to the USA and Canada and within these countries: here the cartridge must be completely empty before the flight. Electronic avalanche airbag backpacks, on the other hand, can be transported without prior notification and without restrictions.

An important psychological aspect of mechanical avalanche airbags is that the recurring cost of deploying an airbag could cause the user to hesitate in an emergency situation. This is particularly problematic if you are unsure whether a potential avalanche will actually cause a burial or whether it is just harmless loose snow that slides along.

Different Cartridges and their properties (by Mammut)

The ABS P.RIDE system should be mentioned as a transition to electronic systems. Although it is categorised as a mechanical system as it has a pressurised gas cartridge, the system also contains electrical components that allow the airbag to be triggered via radio. An electric igniter generates pressure, causing the gas cartridge to be pierced by a needle. The trigger system is powered by a lithium-polymer battery. A major advantage is that the 20% non-triggering rate mentioned above can be reduced by partner triggering. However, this system also has some disadvantages: All ski touring partners must have the same backpack, the system contains temperature-sensitive electrical components, and all partners may need to have their cartridge and release unit replaced after an accidental release.

Advantages of mechanical avalanche airbag systems

Lighter weight than electronic systems
More favourable than electronic systems
Temperature stable
Large range

Disadvantages of mechanical avalanche airbag systems

One-time use (per cartridge)
Replacement of the gas cartridge
Recurring costs
Restrictions when travelling by air

The following table provides an overview of the current mechanical avalanche airbag systems (as of 2024) as well as an allocation to the release mechanisms and air or gas pressure systems described in the article.

Mechanische Systeme
System	Deployment Mechanism	Cartridge Content^*	Brand
ABS Easy Tech	mechanical	N₂	ABS
ABS Solid/ P.RIDE	pyrotechnical	N₂	ABS
Alpride 2.0	mechanical	CO₂and Ar	ABS, Scott, Black Diamond, Ferrino
Avabag	mechanical	N₂ or Air pressure	Ortovox
Float Airbag 2.0	mechanical	Air pressure	BCA
Removable Airbag System 3.0/ Protection Airbag System 3.0	mechanical	N₂ or Air pressure	Mammut
Reactor 2.0	mechanical	N₂ or Ar	Arva

*N₂ = nitrogen, Ar = argon

Electronic systems

Electronic airbags must be charged and switched on before use. As soon as the handle is pulled, a mechanical cable activates the inflation mechanism. The battery or supercondesator supplies a high-speed fan that draws ambient air into the airbag.

Battery operating systems

In battery-powered systems, the energy is stored chemically and converted into electrical energy when the airbag is deployed, which is then converted into mechanical energy by the high-speed fan to inflate the airbag.

The only battery-powered system currently on the market is the JetForce system, which is used in Black Diamond and PIEPS avalanche airbag backpacks. The JetForce system uses a lithium-ion battery that allows four or more airbag deployments per charge. It also allows the airbag to be refilled at regular intervals (approximately every 20 seconds), which means that its volume can be maintained even if it is damaged. After three minutes, the airbag deflates and creates an approximately 200 litre breathing cavity for the trapped person, which can offer a significant survival advantage. The Jetforce battery is said to be operational down to -30 °C, but both very high and low temperatures shorten the service life. At lower temperatures, the capacity of batteries decreases, which reduces the energy output. Batteries perform less well at low temperatures because the chemical reactions that generate electricity are slowed down. This increases the internal resistance and reduces the capacity of the battery. In the Jetforce system, this is compensated for by installing a battery that is actually much too large. Four airbag inflations per charge are rarely actually required. However, if you can use the airbag four times on a full charge, you can be sure that it will still function reliably even when the battery is low and at very low temperatures.

The only other battery-powered system that never made it to the European market was the Arc'teryx Voltair. This system was powered by a lithium-polymer battery. Such batteries use a polymer electrolyte instead of a liquid electrolyte and have a higher energy density than conventional lithium-ion batteries. However, Arc'teryx now points out that the Voltair system should not be used at temperatures below -20 °C. The poor temperature stability of the lithium-polymer battery was the decisive factor in the recall of the product.

Advantages of battery-powered avalanche airbag systems

Easy and free testing
No recurring costs
Multiple activations with a single battery charge
The airbag deflates to form a breathing cavity with air
No restrictions when travelling by plane

Disadvantages of battery-powered avalanche airbag systems

Heavy system
More expensive than mechanical systems
Little choice
Slow charging
Limited battery life
Battery performance decreases over time (extreme temperatures)

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Supercapacitor systems

In supercapacitor-powered systems, the energy is stored electrostatically and converted into electrical energy when the airbag is deployed, which is then converted into mechanical energy by the high-speed fan to inflate the airbag.

There are different types of supercapacitors. However, so-called double-layer capacitors are used in avalanche airbag systems. A double-layer capacitor stores energy electrostatically by forming a double layer at the interfaces between the electrode material and the electrolyte. Compared to batteries of the same mass, supercapacitors only have around 10 % of the energy density. Their power density, on the other hand, is around ten to a hundred times higher, which means that supercapacitors can be charged and discharged significantly faster. Fast discharge is ideal for applications in airbags. Supercapacitors are also significantly lighter than conventional batteries and less sensitive to temperature, as the energy is stored electrostatically instead of chemically. This means they can be used in a wide temperature range without compromising their performance. Supercapacitors have a more stable charge and discharge cycle as there is no chemical reaction, giving them a long life. They can go through millions of charge cycles without losing performance. However, due to their limited energy storage capacity, only a limited number of activations are possible per charging unit. For this reason, supercapacitor-operated systems also require a battery that maintains the charge level of the supercapacitor and can recharge the supercapacitor after the airbag has been deployed to enable multiple deployments.

There are currently three supercapacitor-powered systems on the market. The Alpride E1, the Alpride E2 and the Litric system. Wobie Alpride E2 is the newer and improved version of Alride E1. The Alpride E2 system consists of three double-layer capacitors and two AA batteries. This means that the airbag can be used for up to three months without recharging. After the airbag is deployed, the supercapacitor can be recharged within 40 minutes from the AA batteries (or within 20 minutes with a power connection).

The Litric system consists of nine double-layer capacitors and a non-removable, rechargeable lithium-ion battery. Litric claims an operating time of 90 hours without the need for recharging. Charging can only be carried out with a power connection and takes 25 minutes.

Advantages of supercapacitor-powered avalanche airbag systems

Lighter than battery-powered systems
Easy and free testing

Fast charging and discharging
Long service life
Less sensitive to temperature
No restrictions when travelling by plane

Disadvantages of supercapacitor-powered avalanche airbag systems

More expensive than mechanical systems
Little choice

Limited energy storage
Requires additional battery

The following table provides an overview of the current electronic avalanche airbag systems (as of 2024) and their allocation to battery or supercapacitor-operated systems as well as their system weight.

Battery operating systems
System	operating with	Weight of System	Brand
Jetforce	Li-ionen Akku	1500g	Black Diamond, Pieps
Supercapacitor systems
Alpride E1	Supercapacitor, 2 AA-Batteries	1280g	Black Diamond, Ferrino, Osprey, Scott
Alpride E2	Supercapacitor, 2 AA-Batteries	1140g	ABS, Alpride, BCA, Black Diamond, Deuter, Millet, Osprey, POC, Scott
Litric	Supercapacitor, Li-ionen Battery	1100g	Arcteryx, Orthovox

[1] Haegeli, P., Falk, M., Zweifel, B., Procter, E., Jarry, F., Logan, S., Kronholm, K., Biskupic, M., & Brugger, H. (2014). The effectiveness of the avalanche airbag. Bergundsteigen

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