Mapping avalanches

Making informed decisions from airborne imagery

To classify the average risk of avalanches occurring in certain regions of Switzerland, scientists need to first account for and then understand the spatial distribution of snow and potential weak layers in the snow-pack. SLF researchers use the Leica ADS100 airborne sensor to capture highly detailed imagery of large fields of snow in the alpine areas. With this remote sensing data, the institute is able to visualise an entire alpine spatial terrain.

“In such remote areas, like these alpine ecosystems, it is difficult to get geodata,” said Dr. Yves Buehler, a SLF scientist studying the dynamics and prevention techniques of snow avalanches. “With the data produced by the ADS100, we are able to accurately map these large areas of snow in such remote conditions, which is exactly what we need.”

With the ability of the ADS100 to provide a full multispectral colour swath width of 20,000 pixels in RGBN, the SLF researchers create high accuracy digital surface models from the imagery to derive volumes of avalanches and map them to see what areas of the Alps may be most prone to these natural disasters. Making comparisons of avalanche warnings with detected avalanche events, researchers can validate and improve the warnings. Avalanche warnings are created to caution those who may be considering entering a certain area of the Alps on a scale of 1, low danger level, to 5, very high danger level.

“The near infrared bans produced by the ADS100, and its clear delineation of the red, blue and green bands, is very important in snow measurement,” said Buehler. “These bands help us classify snow properties, which play a critical role in the development of avalanches. Depending on the snow type at the surface, dangerous formations of weak layers and slabs can arise if additional new snow is covering them. This can lead to higher avalanche danger.”

Explore next chapter: More than just avalanches

Story: Mapping avalanches
Chapter 1: Introduction
Chapter 2: Making informed decisions from airborne imagery
Chapter 3: More than just avalanches