World of Science | Review ISSW2018: Hazard communication and perception

What does a good LLB look like?

The purpose of an avalanche forecast is to inform and, if necessary, warn people who are about to enter avalanche terrain. No matter how high-quality and informative the content of a bulletin may be, if the readership does not understand, read or find it, the objective has been missed. The now widely used, standardized symbols for avalanche problems have proven their worth in this respect. Too much text reduces the motivation to read to the end and makes it difficult for users to separate the important from the less important (Engeset et al., P17.4)

In addition to consistent terminology, it makes sense to organize the information in an "information pyramid" - the most important is at the top and readers can go into further detail after they have perceived the main message. Social media (such as WhatsApp newsletters, Instagram, blogs) have also proven useful, for example to draw attention to complex or special situations. Old snow problems are more difficult for the warning services to grasp and more difficult for users of the bulletins to understand compared to "heavy dump with lots of wind" or "rain up to 3000m". On the one hand, social media channels can be used to communicate corresponding hazards separately; on the other hand, they can also be used to obtain observations from the public, which are helpful for narrowing down problem areas (e.g. "How high has it rained in your area?") (Nairz et al, P17.3)

In Canada, they go one step further: in addition to the usual LLBs, in certain cases there are also so-called Special Public Avalanche Warnings - press releases are sent out and targeted media work is used to inform the general public that the risk is particularly high. Such notifications are issued specifically when human factors are more prevalent and coincide with a critical avalanche situation - for example, on the first nice day after fresh snowfall, if this falls on a weekend in the peak season or at the start of a vacation. This type of communication is not without its challenges, but amplifies the range of the warnings considerably (Clayton & Klassen, O17.10).

In general, everyone more or less agrees that the tools of the modern Internet should be part of the repertoire of avalanche warning services today, even if this may still be uncharted territory in some cases (Ruetz, P17.5).

How likely is likely?

Bulletins often talk about the probability of avalanches being triggered. Sometimes this is high, sometimes low, sometimes avalanches are "possible", avalanches can be triggered "in rare cases", or "spontaneous avalanches must be expected". In English, it's all about words like "certain", "very likely", likely", "possible". While different users agree on what "certain" means, the interpretation of the difference between "likely" and "very likely" is much more vague. ( Tart, O17.9)

In addition to this linguistic and statistical difficulty, it should also be noted that the probability of an avalanche happening can be very high, but the consequences low. Conversely, it is sometimes unlikely that an avalanche will occur - but if it does, the consequences may be very high. Presenting this discrepancy in an LLB and somehow expressing it using the hazard level scale is a communication challenge for the avalanche warning services. Explanatory graphics, in which probability and consequences are plotted against each other in diagrams, have proven to be a good tool in the USA (Tremper, O17.7). In the Alps, to my knowledge, a similar representation is only used in Livigno so far.

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How dangerous is serious?

In the meantime, it has become widely known that the most dangerous levels are moderate (2) and serious (3). This is primarily due to the fact that these two levels occur most frequently and that hardly anyone is on the road at level 4 or 5. This raises the question - which still remains unanswered - as to why exactly people stay at home when it is "large" but not when it is "considerable", and how exactly the word "considerable" is perceived. (Eyland, O17.4)

In addition, the progression of the danger level in the previous days also influences our perception of the current danger. In a Norwegian study, test subjects rated a current level 3 situation more critically if level 4 was issued beforehand, and less critically if there was a level 2 beforehand. These results are also potentially relevant for information on predicted (as opposed to past) hazard level development. (Hovem et al., P17.2)

Another target group are mountain and ski guides, who have to guide their guests safely through the freeride or touring day. Representatives of the Austrian Mountain and Ski Guide Association summarized how the LLB influences the decision-making of guides, or not. They named three different methods for making go/no-go decisions:

• Strategic decision-making with the help of known "rules" - i.e. 3x3 and reduction method, stop or go, etc.

• Analytical decision based on systematic snowpack investigations

• Intuitive decision based on many years of experience and process observation, not to be confused with "gut feeling".

The LLB is indispensable for the strategic methods, but not absolutely necessary for analytical or intuitive decision-making. If the mountain guides decide intuitively or analytically, the LLB has little or no influence on the decision. In any case, it is important that decisions can be clearly and comprehensibly justified. This is particularly relevant in the event of an accident and subsequent court hearing. Whether the judiciary considers the three decision-making methods mentioned to be of equal value, or whether the rule-based, strategic methods are preferred, was posed as an open question. (The Influence of Avalanche Bulletins to the Decision Making of Mountain Guides, Gleirscher, Leichtfried, O17.3, no extended abstract).

Conclusion

Avalanche bulletins provide extremely important information on a highly complex topic for winter sports enthusiasts of all kinds. And summarized in relatively few words, for a diverse audience that has fun in the snow in common, but sometimes no more than that in terms of more precise interests and applications. There may be room for improvement here and there, but the fact that it works so well at all is admirable and thanks to the tireless efforts of many avalanche wardens. Modern communication channels and the possibilities opened up by the internet are becoming increasingly important for avalanche warning, and many warning services are constantly developing and looking for new strategies to make use of technology in the service of winter sports enthusiasts. We say Chapeau and thank you!