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PowderPeople | Frank Techel, Avalanche Warden at the SLF

How good is the bulletin?

by Christiane Eggert 02/02/2021
In his recently completed dissertation, SLF avalanche forecaster Frank Techel investigated how well avalanche bulletins reflect the actual danger situation and whether they are consistent across different regions and areas of responsibility of individual warning services. In this interview, he explains more about his work and his unusual career path.

PG: You have been working at the WSL Institute for Snow and Avalanche Research SLF since 2009 and as an avalanche forecaster in avalanche warning since the winter of 2010. Now you have completed your doctoral thesis in fall 2020 with the title: "On consistency and quality in public avalanche forecasting - a data-driven approach to forecast verification and to refining definitions of avalanche danger" (pdf download). What exactly is your dissertation about?

FT: On the one hand, I looked at the question of how good the quality of the avalanche forecast is, in particular the quality of the hazard level issued. So I investigated the question: was the forecast right or wrong? The answer to this question is very relevant - for avalanche forecasters to recognize where the forecast needs to be improved in the long term, and of course also as a reference point for ski tourers and freeriders who use the forecasts. But unfortunately, answering this question is also very difficult, as a danger level is not something that can be measured. This means that even when checking a forecast, a classification is made by a human being and uncertainties remain.

In addition, I compared the forecast products of the avalanche warning services in the Alpine region. In addition to the issued danger level, I was also interested in whether there are differences and similarities in the content and presentation of the forecast.

PG: What were your results? How good is the issued danger level?

In Switzerland, I evaluated the feedback from trained observers after a day in the field and compared it with the issued danger level. Taking into account the dispersion of the feedback on the same day in the same region, it turned out that on about six out of seven days the forecast was assessed as correct, on one day as too high, and almost never as too low. I also found very similar results for Norway, Canada and Colorado.

PG: And the comparison of neighboring warning services in the Alpine region. Have you noticed any differences?

Yes, I have noticed some major differences, particularly in the hazard level issued. For example, danger level 4 (major) was used much more frequently in France and parts of Italy than in Switzerland or Austria, for example. On the other hand, it was also found that on the same day, the hazard level varied by one level on average on a third of the days across warning service boundaries. It is of course clear that differences between neighboring regions are to be expected if the topography and snow climate differ. If, for example, the main Alpine ridge lies between two neighboring warning regions, such as between Valais (CH) and Valle d'Aosta (IT), then differences are to be expected. In contrast, differences in neighboring regions, such as between Samnaun (CH) and Ischgl (AT) or between Ticino (CH) and the neighboring regions in Lombardy and Piedmont, should be rarer. However, differences in the hazard level issued between these regions were also observed quite frequently in some cases.

PG: And what could be the reason for this?

To find this out, I looked at which area a level applies to, among other things. This revealed something very relevant: namely that the spatial resolution of the avalanche bulletins is quite different. For example, the forecast area in Switzerland is divided into over 100 small regions, so-called warning regions, with an area of around 200 square kilometers. Depending on the situation, these regions can be grouped together by the avalanche warning system. In other countries, such as France, these regions are four times as large, i.e. around 800 square kilometers, or in Norway even 20 times larger than in Switzerland. And it is clear that an avalanche warning system in France or Norway has less flexibility to communicate spatial differences in avalanche danger on the map. And if these differences are expected in a warning region, then the next question is: What do I communicate as an avalanche warner - the most unfavorable corner or an average value? And there are probably also warning service-specific differences in handling.

PG: But are there generally higher danger levels in the larger regions, such as in the French Alps?

Yes, I have observed that. What we have seen in the data is that Switzerland, for example, tends to issue a lower hazard level on average compared to its neighbors, especially when compared to the bulletins in neighboring France and, in some cases, Italy. Whether these differences can be explained solely by the different size of the warning regions is unclear.

PG: Has the design of the avalanche bulletins changed as a result of your findings?

An initial, important outcome of my work was that I was able to demonstrate these differences to the European warning services on the basis of facts. The actually quite logical insight from these results, namely that smaller warning regions allow a more accurate forecast, was then also partly taken up in the revision of forecast products: For example, smaller warning regions were introduced in some cases in the cross-warning service avalanche situation reports in Tyrol-South Tyrol-Trentino that have since been introduced. Something similar can also be seen in the east of Austria, where neighboring warning services work closely together. Here too, some warning regions have been reduced in size. In addition, the situation report is presented to ski tourers in exactly the same look, regardless of whether they are looking at it for Salzburg or Styria, for example. I think these are really great developments that will increase the quality of the products - and therefore the benefits for the user.

PG: What findings from your research could be relevant for winter sports enthusiasts? What can you give our readers on tour?

I would like to give freeriders and tourers the following advice: Always be aware that the products - compared to the bulletin you normally use - may differ. In addition to the danger level, take a look at the spatial resolution and validity period of the bulletin. In addition, the bulletins are much more than just a hazard level. Please always take a look at the other information provided in the bulletin, such as the particularly endangered slopes and altitudes, or the hazard description. Details about the avalanche situation cannot be depicted with the danger level alone and are often described in the text.

PG: Do your findings flow into the creation of the avalanche bulletin?

The findings from my investigations certainly have a big influence. One question I keep asking myself is how to filter out important information from the flood of data and process it for the avalanche warning system so that it ultimately leads to a better forecast.

PG: Statistically speaking, most accidents and fatalities occur at avalanche warning level 3. How do you assess this?

Danger level 3 has a fairly wide range from a "low three", where avalanches can be triggered by people in particular, to a "high three", where spontaneous avalanches can occur. Regardless of the type of triple, it is typical that there are places where avalanches can be triggered very easily and that avalanches can reach a size that is dangerous for people. This wide range of threes is a good example of the fact that, in addition to the danger level, the other components of the bulletin must also be looked at in order to get a better picture of the expected avalanche situation.

PG: According to the SLF winter report, 40% fewer accidental avalanches were reported in 19/29 than on average. Why is that?

There are always "more favorable" years, just as there are really "bad" winters. In the winter of 2019/20, the fact that there were two phases in which the avalanche situation was quite favorable for almost a month each certainly had a positive effect. Then there was the lockdown in spring 2020, which certainly also played a role.

But basically you can say that the average number of avalanche victims has remained constant for many years and is not increasing, even though more and more people are on tour or off-piste.

PG: How does the coronavirus situation relate to the avalanche situation?

That's difficult to assess. You keep hearing about a "run" on snowshoes and touring equipment in the sports stores. Whether the situation will drive more or fewer people onto ski tours remains to be seen. And whether this will lead to more new and inexperienced snow sports enthusiasts off the slopes and thus to more avalanche accidents will be difficult to predict even at the end of the winter.

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PG: Snowshoers are a growing target group, and not just because of coronavirus. What role does this target group play in avalanche damage?

Statistically speaking, snowshoers are less involved in avalanche accidents. Compared to ski tourers, they are less likely to be out and about in avalanche terrain. They have - as my colleague Kurt Winkler has evaluated - a five times lower avalanche risk than ski tourers. However, if an avalanche does occur, it is unfortunately more often fatal. It is therefore very important that snowshoers are aware of the avalanche risk when they are out in avalanche terrain, have their safety equipment with them and inform themselves about the avalanche situation in the bulletin.

We are constantly working to ensure that our product is helpful for anyone who wants to venture off the beaten track in the winter mountains. Also for snowshoe hikers. For example, since 2017 we have also been publishing a daily avalanche bulletin for the Jura (CH), a popular area for snowshoe tours.

PG: With, we are a site for winter sports. Let's talk a bit more about you personally. Where do you come from and how did you get into such a profession?

I originally come from the east of Germany, where people don't really have much to do with snow. I came to Switzerland for work almost 30 years ago. I initially worked as a chef for a few years. Attending an avalanche course in New Zealand then awakened my fascination for snow and avalanches, and especially for looking into the snowpack. I then worked as an observer for the SLF, which is how I got involved with the subject. After a few winters working for a road avalanche service in New Zealand and as a slope patroller in the Engadine, I decided to study geography in Fribourg and Bern. After completing my Bachelor's and Master's thesis in the field of snow, I was lucky enough to get a job in avalanche warning at the SLF in Davos. I was then also able to do my doctoral thesis here.

PG: Wow, so from dishwasher to doctor, so to speak! I suppose this is a superfluous question, but do you still travel a lot in the mountains yourself? And where can you be found? In the ski area or on a ski tour?

I think it's very important not to lose touch with the outdoors. I have very long working days on the warning service in winter, but when I have time off, I'm always outside and, if possible, on a ski tour.

PG: What are your "tools" for the snow? What equipment do you always take with you?

I often make a snow profile on tour. That's why I always have a snow saw, a grid and a magnifying glass with me in addition to my safety equipment. Maybe it's an occupational disease!

PG: Are you more defensive in your profession?

I've witnessed so many avalanche accidents in the last 10 years in avalanche warning. Yes, I think this has shaped me and I'm more of a defensive skier.

PG: How do you behave in a group when touring? Are you always expected to be a "professional"?

Of course, as a "professional" you should behave like one. But whether I act as a guide in a group depends entirely on who I'm out with. If I'm clearly the most experienced, I'm more likely to be the leader of the group. In principle, however, everyone in the group should take responsibility and contribute their opinion.

PG: Have you had any experience of avalanches yourself?

Yes, I've probably gone through the typical learning curve. It was a long time ago, but it was probably like a lot of people: You do courses, go out in the field a lot and at some point you feel like you have a clue. Then I got caught in an avalanche and was partially buried. Fortunately, I was uninjured and only lost one ski. This experience was an important wake-up call that still shapes me today.

This article has been automatically translated by DeepL with subsequent editing. If you notice any spelling or grammatical errors or if the translation has lost its meaning, please write an e-mail to the editors.

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