Expert of the Forest: Steep Terrain and Wind Act Like a Chimney.
- 18 Jul 2023 8:40 am CET
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The steep terrain in the forest fire area in the Upper Valais, combined with the dryness and the persistent wind, is accelerating the rapid spread of the fire, according to an expert. Waldbrandexperte Marco Conedera of the Swiss Federal Research Institute for Forest, Snow and Landscape WSL said that the dryness in the Upper Valais combined with the wind is a "poisonous cocktail" to increase the risk of forest fires. The wind further increases the dryness by evaporating the moisture in the vegetation. In such conditions, even small fires can quickly get out of control. According to the WSL, 90% of forest fires in Switzerland are caused directly or indirectly by humans. Unsafe behaviour such as discarded smoking materials, poorly extinguished fires or hot catalysts from cars or motorcycles left in the forest, as well as arson, can cause fires. In the summer, lightning also leads to forest fires. In the period from 2000 to 2022, the WSL Waldbrandatenbank Swissfire recorded an average of 108 forest fires per year in Switzerland, burning an average of 157 hectares per year, which is equivalent to about 220 football fields. In recent years, however, there have been some outliers. In 2018, with a pronounced dry summer, there were 162 reported forest fires, and last year there were 113. The risk of forest fires has been exacerbated in the last 30 years by prolonged dry periods and warmer temperatures, increasingly affecting forests north of the Alps. In the 2020 National Risk Analysis report, drought was one of the top 10 risks in Switzerland, while forest fire was one of the most common natural hazards.