Put simply, droughts are caused by a prolonged depletion of precipitation in a certain ecosystem or climate over a long period of time. Unlike normal dry spells, droughts are so severe that they can thoroughly dry out va... More »

Droughts are caused by changes in land and sea surface temperatures, atmospheric circulation patterns and soil moisture content. A change in any one of these factors sets up a cyclical chain of events that can result in ... More »

As of October 2015, the California drought encompassed more than 98 percent of the California state, notes SeaMetrics.com. The drought began in 2012, with Governor Jerry Brown declaring a drought state of emergency in Ja... More »

www.reference.com Geography United States The West

A climate graph is a type of chart that uses both line and bar graphs to compare temperature and precipitation in a given geographic region over a specific period of time. In all climate graphs, the date range is represe... More »

A ZIP code map with rainfall history data shows the average rainfall over a specified period of time. The rainfall overlay demonstrates the rainfall distribution, so you can learn which areas of the ZIP code get the most... More »

According to About.com, there are many causes for drought, but the most important one "relates to the amount of water vapor in the atmosphere, as this is what creates precipitation." Moist, low pressure systems tend to b... More »

www.reference.com Science Weather & Tides Rain

In the arctic tundra, the average annual precipitation ranges from 6 to 10 inches. Typically, this precipitation is in the form of snow. The arctic tundra is a cold biome that has two seasons, summer and winter. More »