SnowFlurry 9 2019/20 | Interview with "crust hunter" Patrick Nairz, avalanche forecaster at LWD Tirol

Lukas Ruetz:Patrick, we've known each other for a few years now. For me, and I'm sure for many of our readers too, it was/is strange why you always talk about crusts in the picture of the distribution of snowpack stability. After all, it's the soft weak layers and not the hard crusts that cause us the problems. Where does your particular soft spot for melt or wind crusts come from and what does it have to do with the image for snowpack stability?

Patrick Nairz: Clearly, without weak layers there is no snow slab. It is also clear that triggering a slab has little to do with crusts. However, persistent, i.e. long-lasting, weak layers are often found directly adjacent to crusts. These weak layers are often uniform over large distances. This in turn can result in very large-scale avalanches.

It is therefore important that crusts promote the formation of weak layers on the one hand, while on the other hand they delay the connection of the neighboring snow layers and also "protect" weak layers from being destroyed. This is particularly the case if these are located below the crusts. In accident analyses, however, we also observe the reinforcing effect of a soft snow slab lying above the weak layer due to the deposition of crusts within this slab.

The consequence of this is that a good avalanche forecaster must know as much as possible about the existence and distribution of crusts.

LR: As is well known, an avalanche is always life-threatening, regardless of how it comes about. So are these findings a further step from the pure "snow drive warning system" in the early days of avalanche warning to a real avalanche forecaster that can detect and communicate all problems?

PN: No, this realization has nothing to do with the process thinking that has become more difficult over the years and easier to understand communication. Both are the result of intensive engagement with the subject matter and many years of experience. At the same time, there are also very good developments within the European avalanche warning services, particularly with regard to better communication. Keyword: 5 avalanche problems that have been standardized across Europe.

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Profiling with the snow rummager — With the snow rummager profiling

Lukas Ruetz

Patrick Nairz

LR:I know you technically as a snow mole, whose neuronal structures network anew every season. They precisely reproduce the snowpack structure for every region in Tyrol, every altitude and every exposure and lie before your mind's eye like a map with the distribution of stability and a chronological list of all snowfall and rain events. At least that's the impression I always get. How many snow profiles do you actually dig on average per season and how long do you think about this mosaic of hundreds of snow profiles per day?

PN: I don't count my snow profiles any more than I count my ski or mountain tours. I do it for the joy of my job and exercise. For the winter of 2014-2015, however, I can tell you exactly: our interns and civilian servants got together and gave me a trophy made of Swiss stone pine at the end of the winter season, which consists of stacked rings. The rings of different diameters and thicknesses represent a snow profile of that winter. The trophy reads: "Schneeprofilwödmasta 2015 - 145 Profile".

One of the main parts of my job is to take a close look at all the snow profiles I come across and analyze them as well as possible, not just my own. So it actually happens that I think about processes within the snowpack and the effects of the weather on the snowpack several times a day throughout the winter.

LR:You and Rudi Mair have mainly become known beyond the Tyrolean borders for your 10 hazard patterns. But let's leave those aside for a moment. What would you describe as your greatest contribution to avalanche prevention - apart from pure warning work - so far?

PN: I would still like to mention the book because I personally see it as one of the greatest contributions to avalanche prevention. With it, we have succeeded in making it easier for an interested group of users to perceive obvious dangerous situations by means of pattern-like (process) thinking, which hopefully also leads to an adaptation of behavior. For example, if we take hazard pattern 5 (snow after a long period of cold weather), this means: Pay particular attention. With snowfall, it can become very dangerous very quickly.

Apart from that, for me the blog as additional information to the avalanche report is the next essential contribution to avalanche prevention. The blog has created new opportunities for communication. Pictures, graphics, profiles, etc. make a significant contribution to presenting sometimes complex situations, which cannot be depicted in the avalanche report, in a very clear way. Very high access figures and positive feedback confirm the high level of acceptance of the blog.

LR:The five avalanche problems have been around since 2014, if I remember correctly, and they originated from the thoughts of some Swiss researchers and also a bit from your patterns. For advanced users, they are now usually given higher priority in tour planning than the danger level. Why did it take so long for avalanche problems to be invented in Europe? In America, for example, the Avalanche Characters or Avalanche Problem Types have been around for much longer?

PN: Good things take time. It was the same with the avalanche problems. A Slovenian communication scientist pointed out the misery with the different, sometimes very similar approaches and suggested that the avalanche warning services agree on a standardized, easy-to-understand system. The result was the 5 avalanche problems. The icons were then fine-tuned by the well-known alpine cartoonist Georg Sojer. The 5 avalanche problems are now used not only throughout Europe, but also in the USA by colleagues in Utah. Easy to remember: there are 5 danger levels, 5 avalanche problems, 5 avalanche sizes and 10 danger patterns.

Analysis of a fatal accidental avalanche — Analysis of a fatal accident avalanche

Lukas Ruetz

Patrick Nairz

LR:To yourself: What was your path to becoming an avalanche forecaster like? What did you take away from your training and what essential skills did you teach yourself?

PN: It was clear to me at the age of 16 at the latest that I wanted to become an avalanche forecaster. I have consistently followed this path ever since. Via the "detour" of studying torrent and avalanche control, during which I also attended lectures in Salzburg and Innsbruck as well as courses in Canada, I finally ended up at the Tyrolean Avalanche Warning Service in October 1999. Initially, working in avalanche forecasting was a bit of a leap in the dark, despite having spent countless days in the backcountry before starting the job and despite my training at the time. You can only become a good forecaster if you warn a lot and critically analyze your warnings. This in turn leads to a better understanding of certain processes. In the meantime - after 20 years in avalanche warning - I have a lot of routine, which is good. Nevertheless, this job never gets boring!

LR: Finally: What do you think a normal ski tourer can also implement from your handling of avalanches on your own ski tours? Does it make sense for a winter sports enthusiast to dig snow profiles?

PN: The "normal" ski tourer is well advised to plan their tour conscientiously with the help of the snow and avalanche information we provide, including weather information. We dig up the profiles for them and try to depict as realistic a picture as possible in the avalanche report or blog. This allows ski tourers to concentrate on the information provided. We are happy when prevailing avalanche problems are known, the endangered areas in the terrain are recognized and such places are then consistently avoided.