European risk scale for avalanches

European avalanche danger scale

Avalanche danger warning sign in Austria

The European Avalanche Danger Scale is a rating scale that has been in force in Europe since 1993 for assessing the avalanche danger in the mountains. It consists of five levels with clearly defined and standardized terms in different languages.

There is no danger level at which there is absolutely no danger of avalanches. As the danger of avalanches increases, more experience in assessing the terrain , snow conditions and other factors is necessary in order to keep the risk at an acceptable level.

This risk scale is aimed mainly at winter sports enthusiasts who are away from secured ski slopes. Authorities comply with these warning levels in order to evacuate or block districts and streets if necessary. The operators of winter sports facilities have to close ski slopes due to the danger level or otherwise guarantee the safety of winter sports enthusiasts.

Hazard scale

The risk assessment of avalanches is classified in the European danger scale as follows:

1 (low)

An avalanche can only be triggered if there is a large additional load on very few, extremely steep slopes. No spontaneous avalanches (so-called slides) are to be expected. Generally safe conditions.

2 (moderate)

An avalanche is likely to be triggered in the event of high additional loads, especially on the steep slopes indicated. Larger avalanches are not to be expected. The snowpack is generally well consolidated, except on some steep slopes. Careful route selection with the steep slopes and slope exposures indicated .

3 (significant)

An avalanche triggering is likely even with low additional loads, especially on the steep slopes indicated. In some cases, some medium-sized and occasionally large avalanches are possible. The snow cover is only moderately to weakly consolidated on many steep slopes. Experience in assessing avalanches is necessary. Avoid specified steep slopes and slope exposures as far as possible.

4 (large)

An avalanche triggering is likely even with low additional loads, especially on the steep slopes indicated. In some cases, many medium-sized and multiple large avalanches are possible. The snow cover is only weakly consolidated on many steep slopes. When choosing a route, restriction to moderately steep terrain and attention to the avalanche run-off areas. A lot of experience in assessing avalanches is necessary.

5 (very large)

Numerous large spontaneous avalanches are to be expected, even in moderately steep terrain. The snowpack is generally weakly consolidated and unstable. It is advisable not to go on tours.

Definitions

With three ski sticks of equal length - one of them hanging vertically - you can see a 30 ° steep slope.

Slope:

moderately steep: up to 30 °

steep, steep slopes: over 30 °

Additional burden:

low additional load: for example, a single skier, snowboarder or snowshoe hiker

large additional load: for example a group of skiers without safety distances, a snow groomer or an avalanche explosion

The slope can be determined with various aids. There are also small standards in credit card format that can be placed on the map. A certain distance between two contour lines then corresponds to a certain slope. In the terrain, the slope can be determined with a plumb line, or with other aids such as ski sticks. "Experience" from the summer can also be helpful: a grassy slope interspersed with rocks is usually steeper than 30 °.

interpretation

Avalanche reports often state for which slope orientation , slope inclinations, altitude levels and terrain types which danger level applies. For example, if danger level "3 - significant" applies to north-facing slopes above 2300 m, the lower risk level applies below 2300 m and on west, east and south-facing slopes.

It should be noted that the risk increases exponentially: The range covered by the "significant" level is significantly greater than that of the "low" avalanche risk. So if danger level 1 applies in a larger area, the smaller sub-areas are also safe, while with level 3 the avalanche danger has to be constantly reassessed over a small area. If at danger level 3 a moderately steep terrain can still be negotiated with an acceptable risk, a steep slope can be life-threatening at the same danger level.

Historical development

The European Avalanche Warning Services have been working together since 1983 in a working group that meets every 1–3 years. The goals are to exchange experiences, improve international cooperation and standardize. An important result was the standardization of the danger levels in the avalanche reports or avalanche bulletins .

Up until 1993 there were different risk scales in the Alpine countries: France and Italy had an eight-point scale, Switzerland a seven-point scale, Germany and Austria a six-point scale. The now valid uniform risk scale with 5 levels defines and standardizes the terms in the individual European languages.

In 2003 some terms were redefined:

Additional burdens (large: including large groups, snowcat; low: including individual people)
Slope
Avalanche sizes

This basis adopted in 2005 for the uniform definition of the danger levels in the avalanche reports is known as the Bavaria Matrix .

However, following the definition of a common European risk scale, an important task remains to apply these risk levels as uniformly as possible.

criticism

The often proclaimed level 3 often leads to criticism from experts, since most avalanche accidents occur at this level. Many people would compare the system with grades or significantly not assess properly.

Individual evidence

↑ ^a ^b European avalanche risk scale with recommendations ( memento of the original from December 25, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. on the website of the WSL Institute for Snow and Avalanche Research SLF . Retrieved December 25, 2015. @1@ 2Template: Webachiv / IABot / www.slf.ch