Rapid global hazard forecasting to support early action in data poor regions

In March 2022, the United Nations set as a five year target that every place on Earth should be served by Early Warning Systems (EWS) for natural hazards. Such an EWS provides emergency alerts when a natural disaster is imminent and can support local or international (aid) organizations to take effective action early on. Places most vulnerable to natural disasters are often those where little local data and capacity is available to locally develop and operate such a system. As local EWS are not yet available everywhere, robust and reliable global approaches and collaboration initiatives are needed as initial and possible fallback solution.

We propose an innovative flood hazard mapping method based on globally available data that can spatially indicate oncoming floods and thereby inform on preparatory actions to take, such as required emergency stocks, needed shelter capacity, clearing of evacuation routes, and strategic protection of vulnerable people and assets. It instantaneously calculates forecasted flood extents based on global precipitation forecasts and the terrain’s natural drainage network. Its functioning is demonstrated for a selection of historical flood events and shows to good agreement with satellite-observed inundated areas, even where flood extents have gone beyond catchment boundaries. The method can easily be scaled-up to other areas around the world and can be expanded to issue automated warnings and provide impact estimates.