There is a drought in Europe – in some parts there are severe floods after a long drought. A road is flooded here in Cornwall, UK – but how are drought and flooding linked?
This experiment by a British meteorologist explains how the two factors interact. Robert Thompson of the University of Reading inverts a beaker of water onto dry, moderately moist and moist soil in the university garden.
Within a few seconds, the moist floor absorbs the water from the cup. On the only moderately damp lawn, the liquid seeps away more slowly. However, the dry soil hardly gets wet and does not absorb the water. Rather, a kind of pool forms on the dry surface. This phenomenon is the cause of flooding after a severe drought. Thompson breaks off the experiment on the dry ground after 4.30 minutes and shows on a small scale what can lead to violent destruction on a large scale.
The heat is also continuing in Germany: satellite images show the extent of the drought compared to last year. The heavy rainfall announced for the coming days will put an end to the heat – but Thompson’s experiment shows that caution is still required in the event of heavy showers in dry areas.