Flooding is the world’s most expensive type of natural disaster. The cost of global flood damage is hundreds of billions of euros. The Pakistan floods of July 2010 alone caused more than €7 billion euros of damage.
Floods can occur in coastal areas or close to rivers. When huge sheets of water cover low-lying areas, they can cause immense damage to property and threaten lives.
European space technology is a key weapon in the fight against floods. The first line of defence is provided by the Meteosat and MetOp weather satellites. These show developing storm systems and allow accurate forecasts of wind and rain.
Ordinary cameras can show flooding in daylight, when skies are clear. But floods usually occur beneath a blanket of cloud.
ESA’s Envisat and ERS-2 spacecraft carry radar instruments that can see through the cloud, day or night. These provide accurate land use maps of the flooded areas, showing whether the water has covered fields, woodland or built-up areas.
Radar data can even indicate how much water has soaked into the soil and whether the “sponge” is full. By using satellite data of past events, it is also possible to plan for future floods.