Monitoring the 1996 drought using the standardized precipitation index

Droughts are difficult to detect and monitor. Drought indices, most commonl y the Palmer Drought Severity Index (PDSI), have been used with Limited suc cess as operational drought monitoring tools and triggers for policy respon ses. Recently, a new index, the Standardized Precipitation Index (SPI), was developed to improve drought detection and monitoring capabilities. The SP I has several characteristics that are an improvement over previous indices , including its simplicity and temporal flexibility, that allow its applica tion for water resources on all timescales. In this article, the 1996 droug ht in the southern plains and southwestern United States is examined using the SPI. A series of maps are used to illustrate how the SPI would have ass isted in being able to detect the onset of the drought and monitor its prog ression. A case study investigating the drought in greater detail for Texas is also given. The SPI demonstrated that it is a tool that should be used operationally as part of a state, regional, or national drought watch syste m in the United States. During the 1996 drought, the SPI detected the onset of the drought at least 1 month in advance of the PDSI. This timeliness wi ll be invaluable for improving mitigation and response actions of state and federal government to drought-affected regions in the future.