Statistical methods, in particular probability calculations, are frequently used to learn something about the future from the past. However, statistical statements on extreme precipitation events are fraught with major uncertainties as the latter very rarely occur. One way of dealing with uncertainties is to think in terms of scenarios. To do so we develop storylines, that is, chronologies of physically plausible events and their impacts. Flood Dynamics – an online tool of Mobiliar Lab – uses maps of storylines, so-called storymaps, to depict possible extreme flooding. The storymaps are based on physical models that are linked to each other – from extreme precipitation scenarios and nationwide flow regimes and flood models through to estimates of the impact on persons, buildings (damage to buildings, hospitals, schools, retirement and care homes) and roads.
Natural hazards and the effects of climate change are perceived through specific events. The depiction of possible events in scenarios is therefore more tangible for most people than the statistical approach. Storylines enable us to illustrate flood risks with a view to possible events (instead of probabilities) and to convey such risks to professional users, political decision-makers and other interested persons. The approach used is a way of building bridges from science to practice.
