The SnowImager analyses the snowpack faster and more objectively than a human creating a traditional snow profile. This saves time in practice. The data helps to warn against natural hazards such as avalanches and floods. It also provides significant insights for climate research. After years of development, the device has now been patented through the European Patent Office.
The WSL Institute for Snow and Avalanche Research (SLF) has obtained a new patent. On 1 January 2025, the European Patent Office issued certificate number EP4212848 for a “snow density measurement instrument” (as it is called in the patent document) or the SnowImager, as the product has been named. The SnowImager analyses layers in the snowpack and identifies boundaries between layers in the snowpack structure. Individual layers may differ in density, for example, and may feature snow crystals of different types and sizes.
Information about the nature of the layers is crucial for avalanche warnings; this helps to identify weak layers that may fracture, leading to avalanches. Although the layering of the snowpack can now be modelled numerically, data from the field remains important. To create these profiles, the nature of the snow layering is usually recorded manually, which takes a lot of time. The SnowImager aims to make the process much faster and more objective. “It also offers better resolution”, says SLF physicist Benjamin Walter, a member of the development team. This means that the SnowImager has the potential to replace traditional, manual snow profiles in the long term.
Penetrating the snowpack with infrared
To achieve this, the researchers employ optical effects. The SnowImager’s numerous light-emitting diodes send near-infrared light into the snow that is invisible to the human eye. In the first pass, two small cameras in the device measure how much of this light returns.
In the second pass, the front of the device is covered by a panel with a slit. The lower the density, the deeper the light penetrates the layer of the snowpack. And the deeper it penetrates, the further it spreads laterally. However, the cameras only measure the portion of the light that returns through the slit. Combining the measurements taken with and without the covering shows how the snowpack is structured; more precisely, it shows the density and grain size of the various layers.
The device isn’t only designed for avalanche warning services. Snowpack density also plays an important role in providing timely flood warnings. In Switzerland, floods cause more damage than any other natural hazard. The SnowImager data also provides climate researchers with insights into how climate change is altering snowpacks around the world.
Co-founder wanted
The SLF now has three devices available for loan to research institutes and experts who want to test it out in the field in exchange for a cost-covering fee. There has been a great deal of interest. “One device is currently at the University of Oslo in Norway, and we’ve also received an enquiry from the USA”, says Walter.
The next step is for the SnowImager to enter series production. SLF’s collaborative partner Davos Instruments, which is supporting the project, is currently looking for one or more people to co-found a company to produce the SnowImager.
This has been a long time coming. In 1995, the SLF used infrared film to create images of the snowpack at the nearby Flüela Pass. The aim was to show a snow profile in different shades of grey. The attempt was successful, and the layers were clearly visible. A doctorate was written on the subject between 2005 and 2007, and a device was later developed to determine the grain size of the snow. Density measurement remained a laborious manual task. The idea for a possible solution emerged during the coronavirus pandemic, requiring several years of development. In addition, numerous tests were conducted in Davos and under extreme conditions in the Antarctic to develop the SnowImager to the point of patenting.
Text: Jochen Bettzieche