Water in the Desert Deserts exist because the climate is extremely dry. Nevertheless, deserts do receive some precipitation, in the form of rain and sometimes even snow. This occasional moisture is vital to desert flora and fauna and usually triggers an outburst of plant growth and blooming. When rain comes in the desert, it is often just as extreme as the heat.
Flash flooding is common and spectacular.
Flash flood waters cascade down a desert road, temporarily blocking traffic. A once-dry canyon becomes a river. A trail sign points the way to a raging river. What looks like a lake is usually a dry sandy wash. Water can also come in the form of snow.