Oberflächenreif

Surface frost is certainly one of the most impressive crystal forms that we can admire: Beautiful to look at, especially when it glitters and sparkles in the sunlight. However, if it is covered by snow, it turns into a highly dangerous and treacherous weak layer. As is so often the case, beauty is so close to danger.

First rain up to high altitudes, then several days with warmer than average temperatures for the time of year, and then the long-awaited fresh snow finally fell from the sky.

From 12 to 13 December, a warm front swept in and quickly dashed the anticipation of a white Christmas. Accompanying the rise in temperature, it rained in some areas up to around 2000-2300 m, but the amount of rain was quite low. During the night from 13 to 14 December, the temperature dropped again and it cleared up. The snow surface, which had been moistened by the warmth and rain, cooled down again and a cover formed - resulting in broken slush.

A recent find on the Internet: "No winter without old snow problems - that's annoying!" We take a more nuanced view of this statement and put it into perspective: How is an old snow problem defined, what exactly does it look like at the moment and are all old snow problems a big problem for us?

In South Tyrol, East Tyrol and Upper Carinthia, there are currently some easily triggerable weak layers in the snowpack at certain altitudes and exposures. We take a look at two current profiles from East Tyrol.

Avalanche warning services, PowderAlert and WeatherBlog have intensively discussed the current situation regarding the intensive new snowfall in the south and the build-up of old snow cover. That's why we're devoting ourselves here to an exemplary snow profile from mid-November. How do you read it and how do you interpret it?

Tour planning proved to be rather difficult last week, as an old snow problem in the terrain is not easily recognizable. This makes it all the more important to use your head when planning at home and choose a suitable tour carefully.

The International Snow Science Workshop (ISSW) brings together scientists and practitioners from a wide range of snow-related fields every two years. New findings and research results are presented in various thematic blocks - so-called sessions. We break the whole thing down into more or less digestible morsels and summarize the sessions of the ISSW2018 for you every two weeks.

Snow crystals begin to change on their way from the cloud to the ground. Perhaps a layer of air is warmer and the crystal thaws slightly, or several crystals stick together to form large flakes. If it is windy, the fine branches of the crystals break off. Once they reach the ground, things don't calm down - that's when the changes really begin. For skiers, the decomposing and building transformation is crucial:

At first glance, snow profiles seem complicated. However, if you know a few basic terms, this impression is quickly put into perspective. But even if you can read profiles, it takes some practice to draw the relevant conclusions from them. The most important thing, however, is to be able to visualize the snow cover and its layering in the terrain. An example:

The past weekend up to and including Monday was characterized by sunshine and high fog throughout the Alps. We count Monday as a weekend because the WeatherBlog suspects that some people took Monday "Finally the conditions are right for that steep tour I've always wanted to do". And anyway, every beginning of the week is also the beginning of the previous weekend.

Avalanche warning is also a joint project for all of us. This week in SnowFlurry, we discuss why it is not only important to report avalanche accidents, but also special observations of snow and its transformation processes.