Lecture tip | Does it make a difference who hits the compression test?

The aim of stability tests is to obtain information about the fracture behavior in weak layers: Where in the snowpack does the block break and at how many impacts? Does the fracture extend through the entire block or is it only an irregular partial fracture? We then use the test results to draw conclusions about the avalanche risk, even if the interpretation is not always easy or clear.

It seems reasonable to assume that a 190cm tall person weighing 100 kilos will hit the block differently than a smaller, lighter person. But how do you quantify this? Developing a measurement system was the first part of Griesser's work, details of which can be found in the video.

Presentation:

• People with longer arms and higher body weight tend to cause higher tension when hitting the block than people with shorter arms and lower body weight. However, there are outliers and the fluctuation range is relatively high. In other words, even smaller people sometimes hit the block very hard.

• The lower the sensor, the smaller the differences. The tension increases less with weight and arm length at greater measuring depths than further up in the snowpack.

• The arm length and the weight of the arm have a correspondingly smaller effect if you only move your wrist. The dispersion is therefore smaller for hits from the wrist than for hits from the elbow or shoulder.

Conclusion

These results are not yet very helpful for the practical assessment of the situation on the slope, but they form an exciting basis for further investigations in this direction. The answer to the title question is yes. Griesser also emphasizes that the spatial variability of the snowpack may be a much greater uncertainty factor for the test result than the stature of the person striking the snow.