Outdoor fires have been banned in parts of southern Switzerland as several weeks of drought have left the ground and undergrowth tinder-dry.
The Environment Office issued a warning on Monday about the dangers of fires in general, and called for people to take care even in areas where the local authorities have not issued specific instructions.
Barbecues are popular among the Swiss and specially equipped outdoor grill areas are to be found in many forests.
The Swiss weather service, Meteo Swiss, says that parts of cantons Valais and Graubünden have had less than 20 per cent of their normal rainfall in the last two months, while other areas further north and west have received only about one third.
The southern canton of Ticino has banned all outdoor fires, while its neighbour Graubünden has banned them in and near woods.The authorities in Valais say they, too, face a strong fire risk in some parts.
The Environment Office says that where the risk is highest, it will only be dispelled by heavy rainstorms. Brief showers or thunderstorms will not be enough.
The office adds that water levels are low, particularly in the lakes of western Switzerland and in some of the larger rivers, like the Aare which flows through the Swiss capital, Bern. In many places ground water levels are also low.
On April 3 the water level in Lake Biel was ten centimetres lower than the previous record for the same day and was 39 centimetres lower than the long-term average for April.
swissinfo.ch and agencies