|Weather Reference - Drought
Droughts | Disclaimer
Droughts are not merely caused by low rainfall. Drought is a relative term based on expected rainfall for an area at a given time of year. Precise definitions of drought vary greatly from country to country.
In America a drought is classified when an extensive area receives 30% or less of it's normal rainfall over a minimum twenty one day period.
There is sophisticated system of measuring drought called the Palmer
Drought Severity Index, which weighs up the balance between incoming water in the form of rainfall and stored moisture in the soil and outgoing water in the form of evaporation from land and water surfaces, and the absorption and transpiration of soil moisture by plants. This information is then checked against climatic data and expressed as a negative or positive figure that represents the area's water level.
A drought may break over a period of months with the gradually return of normal rainfall.
The linking of sea surface temperatures with droughts is an advance in long term forecasting and may pave the way for future predictions.
All information is presented in good faith. We cannot accept any liability for any incorrect or incomplete information. You are strongly advised to seek clarification on any information presented. If you find any errors or omissions, please contact us to let us know so that we can put it right.