Skyfall som orsak till extrem jorderosion

Sammanfattning: Heavy rain may cause significant erosion and damage to natural and anthropogenic landforms. The purpose of this paper is to describe the most extensive events of soil erosion from heavy rain that are recorded in Sweden and how the prerequisites of this weather phenomena is affected by different future climate scenarios. The described events are Falu Coppermine 1666, Fulufjället 1997 and Hagfors 2004. Information about future conditions for heavy rain is from the climate model program of the Swedish Institute of Meteorology and Hydrology (SMHI). In all the described places, there is considerable declination, which is a much contributing caused by erosion. Slope erosion takes place when the soil is saturated with water and starts sliding. The Swedish Civil Contingencies Agency (MSB) and the Swedish Geotechnical Institute (SGI) have used 17° as threshold value when making inventories of areas subject to risk of rapid soil erosion. The composition of the vegetation and the soils affects the ability to absorb water and withstand erosion. Areas sensitive to erosion has been identified but the occurrence of extreme heavy rain is hard to calculate, as its appearance is difficult to predict as it depends upon incidental local factors. The climate modeling’s of the SMHI indicates however, an increased intensity of the heaviest rainfalls even at relatively moderate global temperature increases