This experiment by a meteorologist shows the effects of droughts - and how they increase the risk of flash floods after rainfall. The video, made by Dr Robert Thompson from the University of Reading, shows three glasses of water being poured on wet grass, moist grass and dry grass.
The experiment was carried out in Harris gardens, at the University of Reading. The water from the first glass is absorbed into the ground in about ten seconds, the second almost 50, and the third takes so long that Dr Thompson gives up.
Dr Thompson explained that this is because dried-out soil repels water rather than absorbing it, causing rain to pool on the surface. He said: "Dry compacted soils repel water rather than letting it soak in as wet soil would. This means rain pools on the surface and runoff rates increase – leading to a greater risk of flash flooding," he continued.
