Snow profile

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Snow profile: The different depths of the finger / fist marks indicate the differences in hardness

A snow profile , also known as a pile / layer profile (RSP), is a cross-section through a snow cover that is created to examine the individual layers. In this way, the various layers in the snow become visible and can also be further investigated with regard to parameters such as hardness, type of snow / grain shape and water content / moisture. These allow conclusions to be drawn about meteorological influences at the time the respective layer was formed (fresh snow, rain, wind, solar radiation, etc.), but also later developments within the snow cover (intrinsic pressure, slope, etc.).

execution

Usually, a snow profile is carried out with the help of an avalanche shovel by digging the snow cover vertically in its entire thickness. The layer-by-layer structure of the snowpack becomes visible and the thickness of the layers can be analyzed. Now the hardness of the individual layers is usually examined. With the simple hand profile, the individual layers are exposed to impacts with different loads and it is checked at which level penetration is possible. The hardness scale for the simplified snow profile comprises 6 levels: fist (very soft), four fingers (soft), one finger (medium hard), pencil (hard), knife (very hard) and ice. If two layers lying on top of one another differ by more than 2 degrees of hardness, there is an increasing risk of avalanches, since such differences in hardness can lead to tension in the snowpack.

Finer differences in hardness are worked out in more precise analyzes with a brush. With experience, you can reconstruct the course of the weather for an entire winter.

An alternative is a layer profile that is thinly excavated from two sides so that the layer structure can be viewed in light shining through.

application

For a long time, the snow profile was recommended as a standard measure for assessing the avalanche risk for winter sports enthusiasts. In recent decades, the snow profile as a method for assessing the avalanche danger has been subject to strong criticism. Modern avalanche research has found that snow profiles are often not very representative. This means that zones with extremely different snow cover structures can be located close to one another on the same slope, so that it is difficult to draw conclusions about the conditions in the surrounding area from a snow profile. Above all, the closure of snow profiles created in flat terrain on steep slopes is considered problematic.

It is also criticized that the hardness determined in the snow profile says little about the connection between the layers, which is decisive for the slab risk. So only possible sliding layers can be recognized in the snow profile, but their actual stability cannot be assessed. This can only be determined with a sliding block .

Even if the assessment of individual slopes based on a snow profile is no longer recommended today, it is still used by avalanche researchers to prepare avalanche reports, for example . It is also used in training to illustrate the layered structure of the snowpack.

literature