Cantonal rules split Swiss forest fire warning map

Forest fire danger levels can change sharply across Swiss cantonal borders, with similar conditions producing different warnings, SRF reported on Wednesday. In Eggersriet in St Gallen canton, the danger level was 4, the second-highest of five levels, while neighbouring Rehetobel in Appenzell Ausserrhoden had level 2.

The differences are linked to Switzerland’s federal system: the cantons are responsible for assessing forest fire danger. The Federal Office for the Environment’s national map can therefore appear as a patchwork of different levels.

In St Gallen, representatives of the building insurance authority, fire services, the military office, cantonal communications department, civil protection and municipalities meet weekly to assess the situation, according to Joel Rodi, deputy head of civil protection in the canton. Local foresters also provide assessments. During periods of acute danger, the meetings are held more frequently.

The assessment uses forest fire indexes, which are computer models that analyse soil moisture, air humidity, wind and precipitation before issuing a recommendation. Local foresters then assess conditions in the five forest regions of St Gallen, including the moisture deeper in the soil and the amount of combustible material, such as leaves and dry branches, on the ground.

Despite coordination with neighbouring cantons, different levels can apply at the same time in the same area along a cantonal border. St Gallen itself can also have different levels in different places, partly because of variations in topography.

Rodi said people should not rely solely on the danger level. It indicates the potential for a forest fire, while the specific measures in force, such as a ban on fires, are also important. St Gallen’s cantonal fire ban was lifted at the beginning of September, leaving municipalities to decide their own restrictions. Rodi said the disadvantage was that each municipality could then have different rules, making communication more difficult.

The federal government plans to standardise the assessment by 2028. The Federal Office for the Environment is working with the cantons on the change and is expected to receive greater powers. The planned system will use the Nearest Fire Day, developed by the Federal Office for the Environment, the Swiss Federal Research Institute for Forest, Snow and Landscape Research and the cantons. Cantonal assessments will continue to be considered, while the cantons will remain responsible for measures such as fire bans.