A new study suggests that strategic reforestation may help to mitigate avalanches in certain areas. SLAB Laboratory, based in Vaud Canton of Switzerland, studies the physics of avalanches using computer-generated models fed with historic avalanche data. Researchers were interested to see how wildfires in 2018 affected the winter avalanche cycles in the mountains around Vaud.
In Europe and North America, forests are drying at an alarming rate. The drying of forests is being driven by a warming climate, which is leading to an increase in wildfires. Long after those fires are extinguished they still pose a threat. Many of the areas that burn in the summer are iconic ski and snowboard destinations in the winter. When it snows in the mountains there will inevitably be avalanches. But how are wildfires and avalanches connected?
Trees as Anchors
Trees can act as anchors for the snowpack. The more anchors on a steep slope, the less likely the slope is to slide (there is always potential the slope could slide). After a wildfire, most trees die, which weakens them over time. These weak trees become poor anchors in the snowpack, increasing the likelihood of an avalanche. This was a large concern in Vaud Canton as the steep slopes that burned are directly above the picturesque Swiss town. Avalanches were previously unlikely in the thickly wooded area. After the 2018 fires, people worried that one avalanche could take out an entire town.
After modeling many different scenarios, researchers from SLAB concluded that strategic reforestation could mitigate avalanches. They determined that a scattered clusters pattern would be the most effective when planting new trees. This pattern would help to dissipate an avalanche’s energy the best. Since avalanches could rip out many of the new trees, reforestation would have to take place over many years to assure full rebound. It is also important to note that these efforts would only work at lower elevations where trees are already prevalent.