Göran Lindström

Flood events recorded by the Swedish Transport Administration and the Swedish CivilContingencies Agency in recent decades have been analysed to create a betterunderstanding of flood problems in Sweden and to guide the development of the warningservice. The results show that floods are most common in the summer and in denselypopulated areas, and usually occur far from major rivers and lakes. An overwhelmingmajority of the events also occurred without any warning criteria being exceeded, either inmeteorology or hydrology, and only a minority of the events were therefore preceded byany warning. To improve the warning service for flood events, it is recommended to (1)develop routines for weighing risk factors from both meteorology and hydrology in futureinterdisciplinary flood warnings, (2) place greater focus on runoff calculations as a riskfactor, especially with short time steps and in densely populated areas, and (3) supplementthe current methodology for evaluating warnings to utilize reported flood events from theSwedish Transport Administration, the Swedish Civil Contingencies Agency or othersources.