Deserts get very little rain, but when they do get rain, it can be terrifying. The hard dry ground can’t soak up much water, so almost all of it runs straight off the surface - pooling, racing downhill, and gathering into rivers in a matter of minutes.
In narrow canyons that have been carved by floods for thousands of years, the water funnels into walls several metres tall that come crashing through, sweeping away rocks, cars, and anything in the way. These flash floods are the deadliest weather in many deserts.
The really sneaky part is that the storm doesn’t have to be near you. A thunderstorm 30 kilometres away over a mountain range can send a flood roaring down your canyon under a totally blue sky. Park rangers warn hikers to climb to high ground if they hear distant rumbling.
