ABSTRACT
Floods in Norway are caused by snowmelt in the spring or early summer, often in combination with rainfall. The large basins in southeastern Norway span large lowland areas, areas in the hills and low mountains, and alpine areas. In most years there are two or three flood peaks. Many of the largest floods in western Norway are caused by extra-tropical cyclones on the polar front. A major flood affected the large rivers in Buskerud and Telemark counties in the southeast in early July 2007. It was mostly caused by long duration rainfall, but with some contribution from late snowmelt in the most mountainous parts of the basins. Autumn floods occur almost every year somewhere on the coast of Nordland. There were severe autumn floods there in October 1922, 1931, 1949, 1959 and 1962. The Norwegian flood database comprises documentation with meteorological analyses of a large number of rainfall floods since 1900.
