by: Aavudai Anandhi, Mary Knapp
Volume 2016, No. 1, 23 May 2016
Drought is a complex, least understood and one of the most expensive natural disaster. Drought impacts many sectors of environment and society. A regular question is how a current drought compares to previous droughts. Water managers, resource managers, news media and the general public want to place the event in context as they evaluate impacts, and as they attempt to plan for future events. There are many definitions of drought (meteorological, agricultural, hydrological and socioeconomic) resulting in a large number of drought metrics and indices in literature. In this study we have used Standardized Precipitation Index (SPI), a useful tool to answer these questions. SPI is a transformation of the probability of a given amount of precipitation in a set period of months. This allows for the comparison of wet/dry spells over extremely different climates and over various time scales from one month to two years (24 months).