National Drought Mitigation Center

Drought Monitoring Tools

U.S. Drought Monitor & Related Products

U.S. Drought Monitor

The U.S. Drought Monitor is a weekly assessment of the extent and severity of drought in the United States.

NDMC Objective Blends

Objective blends combine different gridded datasets into a single map, weighted to account for differences in the eastern and western parts of the country. The blends are combinations of the Standardized Precipitation Index, the Standardized Precipitation and Evapotranspiration Index, and soil moisture data.

Drought Impact Toolkit

The Drought Impact Toolkit is a collection of tools for monitoring drought impacts, based on news, social media, crowdsourcing and citizen science, as well as links to other tools and places to look for drought impacts. It also has a collection of post-drought assessments, mostly by different state agencies, that examine how past droughts have affected people, livelihoods and the environment.

Condition Monitoring Observer Reports (CMOR)

The Condition Monitoring Observer Reports (CMOR) system is a way for people to provide photos and observations about the effects of drought. Reports appear on an interactive map.

Drought Impact Reporter

The Drought Impact Reporter is a historic archive of the effects of drought, based mainly on media reports back to 2005. It is a good starting point if you want to see how drought has affected livelihoods and the environment for a given area.

North American Drought Monitor

The North American Drought Monitor, produced monthly, shows the area and intensity of drought.

U.S. Agricultural Commodities in Drought

We overlay the U.S. Drought Monitor on agricultural census data to determine what proportion of different crop-producing areas are affected by drought.

Managing Drought Risk on the Ranch Dashboard

Managing Drought Risk on the Ranch includes a drought monitoring dashboard that incorporates the U.S. Drought Monitor, precipitation, outlooks, grassland productivity forecasts (Grass-Cast), and vegetation drought stress (VegDRI).

Drought Impacts Multi-Tool

The Drought Impacts Multi-Tool allows you to display layers from the Drought Impact Reporter, Condition Monitoring Observer Reports, CoCoRaHS, Drought News, and Drought Tweets, as well as the U.S. Drought Monitor and state and county boundaries. CMOR and CoCoRaHS, the default view, is a particularly relevant comparison.

Choose a Drought Indicator

Handbook of Drought Indicators and Indices

For a list of the pros and cons of 50 different drought indicators in use around the world, please refer to the Handbook of Drought Indicators and Indices. It was developed by Mark Svoboda and Brian Fuchs of the National Drought Mitigation Center at the University of Nebraska-Lincoln, and published in 2016 by the World Meteorological Organization and the Global Water Partnership. A PDF version is also available.

Historic Data & Information

Drought Risk Atlas

The Drought Risk Atlas provides a historic look at drought for a specific location, going back as far as we have good data. See or download precipitation, temperature, or several different drought indices, including the U.S. Drought Monitor, the Standardized Precipitation Index and the Palmer Drought Severity Index.

Historical PDSI Maps

The Palmer Drought Severity index has been calculated by climate division for several time periods starting in 1895.

PDSI by River Basin

Select a river basin to view a graph of the Palmer Drought Severity Index from 1895 to 2004.

Satellite, Climate & Biophysical Data Products

Vegetation Drought Response Index

The Vegetation Drought Response Index combines data from satellites with ground-based measurements and other information to detect drought’s effects on vegetation.

Quick Drought Response Index

The Quick Drought Response Index detects “flash drought,” when heat and dryness combine to change environmental conditions over a few days or a few weeks.

Grassland Productivity Forecast (Grass-Cast)

Grass-Cast uses almost 40 years of historical data on weather and vegetation growth— combined with seasonal precipitation forecasts—to predict whether rangelands in individual grid cells (whose size is 10 x 10 kilometers, or about 6 x 6 miles) are likely to produce above-normal, near-normal, or below-normal amounts of vegetation.

Overview of Weather Water Land Sites (OWWLS)

The Overview of Weather Water Land Sites (OWWLS) maps the location of water and weather station networks across the West that are used by authors of the U.S. Drought Monitor. By gathering the locations of existing weather stations, stream gauges, reservoirs, and other installations in one place, the OWWLS tool can be used to identify gaps in data and inform deployment of future weather stations.

Soil Moisture Detection

Groundwater and Soil Moisture Conditions from GRACE Data Assimilation

NASA’s GRACE satellite mission provides data on how much water is beneath the Earth’s surface. We use it to map soil moisture, root zone moisture and groundwater.

Standardized Precipitation Index

Standardized Precipitation Index

  • Download the program to compute the SPI with your data
  • Learn about the SPI
  • View archived SPI by climate division maps

The SPI tells you whether an area is dry or wet based on its historic record, and can be computed for different time intervals.