Causes of a drought

There are many causes of droughts. When water vapor does not rise to the cooler regions of the atmosphere rain does not fall; causing a drought. Also, a drought can be caused by the change in wind patterns. The change in wind patterns can move clouds and moisture through the atmosphere causing an area to receive less rain or snow for a long period of time. Mountains can causes droughts because they can prevent wind from blowing moisture to areas in need of rain. Lastly, when an area experiences a stalled high pressure system, the area is exposed to excessive sunny weather which causes a drought.

Title: Droughts
URL: http://library.thinkquest.org/C003603/english/droughts/causesofdroughts.shtml