Floods in Germany

Floods in Germany

Subject: Geography

Context: Over a hundred people have died and several people remain missing as a result of flooding in Germany caused by unprecedented rainfall, which is being referred to as the worst such event that the country has witnessed in nearly a century.

Concept:

Floods in Germany caused by

• A severe storm and continuous rains that caused rivers and streams to swell up and flood the towns and cities located alongside the banks of the river Ahr in Germany.
• When the soil and the water bodies were no longer able to absorb the excess water, it spilled out wreaking havoc in nearby areas and causing damage to buildings, infrastructure, the environment and people’s belongings.
• Scientists in Germany have dubbed the low-pressure weather system that caused the weather event “Bernd” devastating floods that were seen in the last few days have never been seen before. Germany floods

Flash floods

• Flash floods are characterised by very fast rise and recession of flow of small volume and high discharge, which causes high damages because of suddenness. This occurs in hilly and not too hilly regions and sloping lands where heavy rainfall and thunderstorms or cloudbursts are common.
• A flood caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. Flash floods are usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them. They can occur within minutes or a few hours of excessive rainfall. They can also occur even if no rain has fallen, for instance after a levee or dam has failed, or after a sudden release of water by a debris or ice jam.
• A flash flood is a rapid inundation of geomorphically low-lying areas

Causes of Flash floods

• A flash flood is a rapid inundation of geomorphically low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields.
• However, floods are not always caused by heavy rainfall. Flash Floods can be caused by a number of things, but is most often due to extremely heavy rainfall from thunderstorms.
• Flash Floods can occur due to Dam or Levee Breaks, and/or Mudslides (Debris Flow).
• In areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat.
• The intensity of the rainfall, the location and distribution of the rainfall, the land use and topography, vegetation types and growth/density, soil type, and soil water-content all determine just how quickly the Flash Flooding may occur, and influence where it may occur