When rain does come

Water in deserts

Rain does fall occasionally in deserts, and desert storms are often violent. USGS A record 44 millimeters of rain once fell within 3 hours in the Sahara. USGS

Normally dry stream channels, called arroyos or wadis, can quickly fill after heavy rains, and flash floods make these channels dangerous. USGS More people drown in deserts than die of thirst. USGS Though little rain falls in deserts, deserts receive runoff from ephemeral, or short-lived, streams fed by rain and snow from adjacent highlands. USGS Although most deserts are in basins with closed, or interior drainage, a few deserts are crossed by 'exotic' rivers that derive their water from outside the desert. USGS

Oases are vegetated areas moistened by springs, wells, or by irrigation. Many are artificial. USGS The remaining surfaces of arid lands include bedrock outcrops, desert soils, and fluvial deposits including alluvial fans, playas, desert lakes, and oases. USGS

A desert can be dry for a long time and still be dangerous in a storm. That is one reason the myths page is worth a look.