Monitoring Drought
Current and Recent Drought Conditions | Historical Drought Occurrence
Because there is no single definition for drought, its onset and termination are difficult to determine. We can, however, identify various indicators of drought, and tracking these indicators provides us with a crucial means of monitoring drought. Determining which indicators to use poses more difficulties for planners: should they rely on data collected for specific parameters (such as streamflow and snowpack), or should they select one or more indices, which incorporate and weigh various types of data in various combinations? Equally important in choosing these indicators is a consideration of the type or types of water shortage facing the planner—an index or parameters well suited to agricultural concerns are of limited use to urban planners.
Understanding the historical frequency, duration, and spatial extent of drought also assists planners in determining the likelihood and potential severity of future droughts. The characteristics of past droughts provide benchmarks for projecting similar conditions into the future.
How to Use this Section
If you are new to the concept of monitoring drought, “Drought Indices”, an NDMC white paper, will give you a good overview of the various kinds of drought indices and their uses. Three newer tools (the Standardized Precipitation Index, Drought Monitor, and Drought Impact Reporter) are highlighted below. Use this section also to explore the many monitoring tools available on the web for exploring current and historical drought occurrences.
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Current and Recent Drought Conditions
Links to news articles relating to drought monitoring
The Standardized Precipitation
Index
The SPI is an index based on precipitation only. It can be used on a variety
of time scales, which allows it to be useful for both short-term agricultural
and long-term hydrological applications. You can download
the SPI program and sample files here.
The Drought Monitor
A comprehensive drought monitoring effort between the USDA (JAWF/NRCS),
NOAA/CPC (NCEP/NWS), NCDC (DOC/NOAA), and the National Drought Mitigation
Center
NDMC’s Drought Impact Reporter
The goal of the NDMC’s Drought Impact Reporter is to collect, quantify, and map reported drought impacts for the United States and provide access to the reports through interactive search tools. Users can submit their own drought impact reports through the tool’s easy web interface.
Early Warning Systems for Drought Preparedness
and Drought Management
The Proceedings of an Expert Group Meeting held in Lisbon, Portugal, in
September 2000
Other Drought Monitoring Tools
A collection of links to sites providing information
on other indices, forecasts, water supply conditions, and global climate
State Drought Impact Monitoring Resources
A collection of links and resource contacts for those areas
of the United States affected by drought
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Climographs of Selected US Cities |
Climographs of Selected World Cities |
Historical Maps of the Palmer Drought Index |
What is Climatology?
A brief explanation.
Links to news articles relating to drought history and related topics
How to Create a Local Drought History
Important Climatology Links and Paleoclimatology Links
Climographs of selected U.S. Cities
Climographs for selected International Cities
Historical maps of the Palmer Drought Index
by U.S. climate division
Historical graphs of the Palmer Drought Index
by U.S. river basin
Drought in the Dust Bowl Years
A discussion of the impacts—social, environmental, and economic—of drought in the United States in the 1930s.
Historical Drought Information in the United States
You can also view other pages to better understand how to assess your drought vulnerability and mitigate the effects of drought.