PartnerNews | More concise use of avalanche problems in the Swiss Avalanche Bulletin

In 2017, the European Avalanche Warning Services EAWS (European Avalanche Warning Services) uniformly defined the following five avalanche problems:

However, there were no clear criteria as to when which avalanche problem is used in the avalanche bulletin. This meant that several problems were often described over a long period of time. As a result, the actual goal was lost, namely to focus on the essentials with the help of the avalanche problems. The SLF is aiming for a more concise use of the terms and has developed new, clear criteria for this.

Wind displacement near the ridge — Wind transport near the ridge

SLF

This is new

Focusing on the most important avalanche problem:

Until now, the avalanche bulletin has often mentioned several avalanche problems at the same time. What is new: As a rule, only the most important avalanche problem is now mentioned in the title (see illustration). If there are other avalanche problems, these are still described in the text, but are no longer mentioned in the title. Only if several problems are similarly pronounced can several continue to appear in the title.

Restricted use of the "old snow" problem:

The avalanche problem "old snow" is now only used in the presence of pronounced weak layers within the old snowpack, in which a snow sportswoman can also create a fracture and thus trigger an avalanche. Avalanches can be particularly large and therefore particularly dangerous in the case of fractures in old snow. In situations where there are weaker layers in the old snow, but where the initiation and propagation of a fracture is less likely, the avalanche problem "old snow" is no longer used.

New term "no pronounced avalanche problem":

If there is no fresh snow, the drifting snow is older than about three days and hardly triggerable, and there are no pronounced weak layers - a situation that was previously usually communicated as an old snow problem - the phrase "no pronounced avalanche problem" is now used.

In the hazard description for the individual regions, only the most important avalanche problem is mentioned in the title (outlined in red), in this case drifting snow. However, if there are other problems, these are still mentioned in the text.

B. Zweifel, SLF

Distinction between fresh snow and drifting snow:

The avalanche problems "fresh snow" and "drifting snow" will be distinguished more clearly in future: In the case of significant snowfall, only "fresh snow" will be used instead of the previous "new and drifting snow". Snow rarely falls without wind, so drifting snow is usually also present. However, the main danger comes from the additional load of fresh snow. Another typical feature of the "fresh snow" avalanche problem is that the danger spots are widespread. In contrast, with the "drift snow" avalanche problem, the danger spots are more localized and usually easier to recognize. The avalanche problem "drifting snow" is only used if the danger is primarily caused by snow drifting.

Important: The changes only affect the use of avalanche problems in the avalanche bulletin. There are no changes to the definitions of the avalanche problems themselves.

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PartnerNews | More concise use of avalanche problems in the Swiss Avalanche Bulletin

Starting this winter, the most important avalanche problem will be highlighted in the Swiss avalanche bulletin.

This is new

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