Spring flood

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Spring flood is a regularly recurring rise in the level of streams and rivers in spring .

A common cause is the snowmelt in spring, with the snowwater flowing away through the mountain streams. This causes the streams and rivers to swell and the water level rises. Even smaller streams can turn into torrential rivers and endanger local residents.

Raging brook in the Black Forest after rain and snowmelt (January 2018)

Due to the winter cold, precipitation is stored in the form of a blanket of snow, in northern Russia and Europe the water is retained until the temperature rises and then shoots in the rivers to the sea as floods in spring. A study by the Vienna University of Technology found, after evaluating 4,262 measuring stations, that the spring floods occur about a week earlier, less snow accumulates, the water runoff is becoming weaker, also for the hydropower plants on the rivers.

In some countries, the spring floods are agriculturally important as the flooding of agricultural land fertilizes the soil.

Heavy rains can also lead to swelling of streams and rivers and thus to floods or intensify them. Scientists also differentiate between summer and winter floods, whereby in winter frozen or already saturated soils can lead to increased runoff - even in the transition period to spring. The melt water coming from the mountains is also added to the current precipitation for the runoff . The sealing of the ground by buildings, traffic areas and roads also reduces the ability to absorb water.

Flood on the Lahn in winter 2018 below one of the bridges in Marburg

In January 2018, for example, the storm Burglind with hurricane gusts to strong wind in a thaw period after heavy snowfall in December also brought continuous rain on the Upper Rhine and in the Vosges , the levels also rose in Upper Franconia and Hesse ( Lahn ); the Neckar as a tributary to the Rhine was closed to shipping. For the Moselle , a water level of 7 meters was measured in Trier on January 4th, a further increase in the rivers in the region was predicted due to a rainy area, the Rhine water level in Cologne initially only showed 7 m (mean water around 3 meters) for the lower reaches of the Rhine , later the level rose above the critical mark, shipping is then stopped.

In contrast to lightning floods, the levels gradually rise after the onset of snowmelt during winter floods, and the process is easy to predict. For the Rhine flood, the Mainz Rhine level is an important local measured variable with a critical flood level of six meters.

List of catastrophic spring floods

Individual evidence

  1. Floods: Climate change is changing floods across Europe. In: Der Tagesspiegel . August 10, 2017, accessed January 9, 2018.
  2. a b Federal Office for Civil Protection and Disaster Assistance : Recommendations for floods. Structural civil protection.
  3. a b After storm Burglind: cities prepare for floods. In: Frankfurter Allgemeine Zeitung . 4th January 2018.
  4. Winter floods are approaching: Precautions are being taken on Kostheim Main Promenade. In: Wiesbaden Courier . 4th January 2018.