Drought -- National Drought Mitigation Center


Date of this Version



American Meteorological Society (April 2011); DOI:10.1175/2010BAMS3103.1


Improved drought monitoring and early warning systems are urgently needed to cope with current and potentially changing drought patterns as we move into the future. Drought is a slow-moving natural hazard that can affect virtually all climatic regimes. Generally defined, drought is a deficiency of precipitation relative to what is expected (i.e., “normal”) that, when extended over a season or a longer period of time, results in the inability to meet the demands of human activities and the environment. As countries around the world begin to establish national drought strategies, one critical component should be the development of a comprehensive drought monitoring system that has the ability to provide an early warning of the drought’s onset, determine drought severity and spatial extent, and convey that information to decision-making groups in a timely manner. This information can then be used to either reduce or avoid the impacts of drought.

With this in mind, drought experts from nearly two dozen nations,1 including from all six regions of the World Meteorological Organization (WMO), were brought together for the Inter-Regional Workshop on Indices and Early Warning Systems for Drought, which was a four-day workshop focused on developing standards for drought indices and guidelines for drought early warning systems (DEWS). The motivation behind this workshop came out of the primary recommendations from the February 2009 International Workshop on Drought and Extreme Temperatures in Beijing, China, where one of the main recommendations was for the WMO to identify methods and marshal resources to develop standards for agricultural drought indices.