Research sheds light on seasonal mortality of river flooding to improve preparedness and recovery from natural hazards at global scale

In spite of their recurrent seasonal patterns, riverine floods affect millions of people and kill thousands every year.

Knowing the average timing and magnitude of floods can help to better prepare for disasters by improving the humanitarian assistance and the management of resources.

A JRC’s research provides estimates of population affected by river floods and corresponding mortality rates in all countries worldwide, as well as their seasonal distribution. It uses a modeling cascade involving hydrologic-hydraulic simulations at spatial resolution up to 1km.

Inundated areas are combined with population distribution to estimate human exposure and then aggregated at the country level. Mortality rates per region and income class are derived from global disaster datasets and used to estimate country averages. Population affected and flood mortality are disaggregated to monthly data according to the seasonal variability of floods over 1980-2018.

An average of 54 million people is estimated to be affected by river floods globally every year. Summer floods in Asia are the main cause of mortality, accounting for 63% of the 6,120 casualties per year globally. In contrast, the six months between November and April contribute to only 13% of global mortality, mostly due to floods in South America and Africa.

The Global Flood Awareness System (GloFAS)

Seasonal mortality rates were produced in the context of the Global Flood Awareness System (GloFAS), part of the Copernicus Emergency Management Service. GloFAS is an operational system for global stream flow modeling, forecasting, and flood early detection in large rivers, with a forecast horizon up to 30 days and a seasonal outlook up to 4 months ahead.

The seasonal analysis of past floods performed in this work is based on the GloFAS-Reanalysis v3.0, the latest version of the global hydrological reanalysis produced for GloFAS through a successful collaboration between the JRC and the European Centre for Medium-Range Weather Forecast (ECMWF). This achievement contributes to the ongoing efforts to expand GloFAS daily services from hazard to impact forecasting.

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Global modeling of seasonal mortality rates from river floods

Data: GloFAS hydrological reanalysis