Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World
Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 232–238.
Flash floods in mountain
areas
MANFRED SPREAFICO
Federal Office for the Environment,
CH-3003 Berne, Switzerland
Abstract The main causes of flash floods in mountain areas are cloud bursts or
stationary rainfall, heavy rainfall and rapid snow melt in high mountain areas,
glacial lake outbursts, failure of dams built up by landslides, rock falls or
debris flows, and overspill following the failure of water power reservoir
dams. The sudden rise and rapid fall of water levels, as well as the high flow
velocities combined with large sediment transport, demand special procedures in
flood risk management. Some approaches to flood risk management in Switzerland
and guiding principles with regard to flash floods, are presented here.
Key words flash floods; extreme precipitation;
debris flows; hazard maps; flood risk management; Switzerland