MBGnet's Virtual 
Desert Biome

Causes of Deserts

Most deserts are found in bands around the world. These bands are at 30 degrees latitude north and 30 degrees latitude south. (between the dotted lines on the map).

Other deserts are caused by the "rainshadow" effect. Rainshadow deserts are caused by mountains. As air moves up over a mountain range, it gets cold cannot hold moisture -- so it rains or snows. When the air moves down the other side of the mountain, it gets warmer. The warm air can hold lots of moisture, so it doesn't rain as much.