Waldbrandursachen & Verhaltensregeln

Causes of forest fires and code of behaviour

Over the last 20 years, an average of 90 forest fires per year laid waste to almost 374 hectares of forest in Switzerland. A good half (57%) of all such fires are caused by human activities. Of these, 12% are accounted for by arson. Over one tenth (14%) of fires are due to lightning strikes and the cause of almost one third of fires (29%) is unknown.

Causes of forest fires

Most meadow and forest fires in Switzerland are caused by human activities and they are often the result of careless behaviour. In summer months, forest fires are also caused by lightning, particularly in the Southern Alps and, increasingly also in recent years, in the Alpine region.

Natural causes

  • Lightning strikes

Deliberate fire-setting

  • Arson


  • Insufficiently extinguished campfires
  • Discarded smoking products etc.
  • Playing with fire
  • Forestry and agriculture (including burning of wood residues and straw, flying sparks from machinery)
  • Military (target practice)

Technical causes

  • Railways (including flying sparks from overhead lines and hot brake pads)
  • Electrical lines (including ignition of branches)
  • Technical equipment (e.g. hot catalytic converters in parked cars)

Particular risk factors

  • Increased presence of people and machinery (leisure seekers, passers-by, forestry workers)
  • Forests and grassland after winters with little snowfall
  • Frequent periods of dry weather or dry winds (e.g. Foehn wind)
  • Dry forest locations with slow decomposition of branch material (coniferous forests, chestnut forests)
  • High proportion of softwood in windthrow areas

The forest fire danger is high during periods of drought and strong Foehn winds, in particular in the Alps and Southern Alps. The situation in spring following winters with low snowfall is particularly critical until the vegetation has sprouted as the sun’s rays fall directly on the dry forest soil and a lot of potential fire material is available on the forest floor. The forest fire danger may change and expand at regional level as a result of climate change.

General recommendations for behaviour when lighting fires outdoors

Forest fire risk refers to the probability with which a forest fire can arise. Forest fire risk can be increased, for example, by leisure activities, making preventive measures necessary even if the forest fire danger is low. Sufficient care must always be taken when lighting fires in the forest and outside the forest – even if the forest fire danger is low or moderate.

You can help to avoid forest fires by following the following general rules:

  • Inform yourself about the local danger situation if you intend to light a fire outdoors.
  • Always obey fire bans!
  • Pay attention to information provided on the internet, radio and television and in newspapers.
  • Never throw lit cigarettes and matches away.
  • Use permanent campfire sites for barbecues.
  • Always monitor fires and extinguish any flying sparks that arise immediately.
  • Ensure that campfires/barbecues are completely extinguished before leaving.
  • Do not light fires outdoors in strong and gusty wind conditions.
  • Only use fireworks in locations that have been expressly authorised for this activity by the local authority.