Desert rivers

For those unfamiliar with the desert, the dry riverbeds, found almost exclusively in the north, may seem like convenient roads or winding paths of firmer ground. However, miles away, in the mountains, rain can quickly form a mighty river, a flash flood that travels down these channels faster than a horse can run.
  Many a wanderer has drowned, and many camps set up in these wadis have vanished in the avalanche of water. Ironically, it is indeed possible to drown in the desert. But as fast as the flood comes, as fast is it gone again, the might of the water second only to the might of the sun.