Flatisen, Svartisen: A Norwegian glacier in decline

The advance and retreat of glaciers, influenced by changes of local and regional climates, can result in dramatic landscape changes. The article, which follows up previous documentation of long-term studies at Svartisen, deals with changes of Flatisen: at the end of the 19th century, this was one of the largest glaciers of West Svartisen, and was supplied by accumulation areas that rose to > 1400  m a.s.l. It crossed the river Glomåga and ascended to 100  m above the valley floor. The river had a subglacial course until the 1920s. A proglacial lake, formed in front of the glacier in the 1930s and became larger throughout the rest of the 20th century. Changes of Flatisen between 1957 and 1990 were monitored during visits to the glacier. After the retreating front became inaccessible by land, photographs were taken. Early this century, the glacier retreated from the lake. A helicopter reconnaissance in July 2017 revealed that the surface was almost wholly below 1000  m a.s.l., the local equilibrium line altitude of recent years. Without a permanent accumulation zone, Flatisen is likely to disappear within the first half of the present century.