New research: Flash floods – why are more of them devastating the world’s driest regions?
Last year, around two-thirds of Pakistan was affected by widespread flash flooding, with more than 1,500 people killed and around 33 million made homeless. Almost 2,000 people died in flash floods across Africa, and parts of the United Arab Emirates, Iran, Saudi Arabia, Qatar, Oman and Yemen were inundated with water. Flash floods are a growing threat in some of the world’s driest regions. Deluges can trigger sudden and rapid torrents of run-off that flow down dry river beds and rocky channels. Because parched soils repel water rather than allowing it to soak in, flash floods can be more devastating in drylands than in wetter areas. Surges can result from relatively small amounts of rain, as little as 10 millimetres in one hour. By comparison, floods in wetter regions typically follow more prolonged bouts of rainfall.