To learn how these definitions can be used in drought communication, visit our Drought Communication page. Short- and long-term droughts differ in the time scales at which they occur, their impacts, and their monitoring. When the supply and demand of various raw materials are affected by drought. However, as the various definitions on the right show, drought can be difficult to define – so difficult that researchers in the early 1980s found more than 150 published definitions of drought that reflect differences between regions, needs and approaches. The worst drought in 50 years affected at least 35 states during the long, hot summer of 1988. In some areas, the lack of rainfall dates back to 1984. In 1988, precipitation in the Midwest, Northern Plains and Rockies was 50 to 85 percent below normal. Crops and livestock died and some areas became deserts. Forest fires began in the northwest, and by the fall 4,100,000 hectares had been burned. A government policy called “Let Burn” was in place for Yellowstone National Park. The result? Half of the park – 2,100,000 acres – was charred when a huge wildfire developed.

The Drought Monitor has been a team effort since its inception in 1999, co-authored by the National Drought Mitigation Center (NDMC) at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Department of Agriculture (USDA). The NDMC hosts the Drought Monitor website and related data, and makes the map and data available to NOAA, USDA, and other agencies. It is available free of charge from droughtmonitor.unl.edu. To help classify and monitor droughts, scientists have defined different types of droughts: there is a lot of information on the Internet about drought and its impact on society. The links below are just a few of the places elsewhere on the internet where you can find more information about drought and where a drought is currently occurring. Although laws have been in place for decades to protect the water sources of local or regional populations by limiting who can use the available water, a change of direction is needed as climate change leads to more frequent and intense droughts. Solutions that prevent non-essential water use, increase natural water storage in soil and aquifers, or maintain water and lake levels can help limit the public health impact of future droughts by increasing the overall supply of usable water. Laws that require green infrastructure measures that collect and store rainwater can also help replenish underground aquifers. Green infrastructure requirements in national or local laws, or in clean water law permits, can help communities capture and retain a certain amount of water that would otherwise have been diverted from the land, leaving dry soils and aquifers depleted. Detecting drought before it intensifies can reduce the impact and save money. How you recognize it depends on how it affects you.

Traditional methods of measuring drought include comparing observed precipitation with what is normal (climatological), comparing soil moisture and harvesting conditions with what is normal (agricultural), or examining the amount of water contained in snow, the level or flow of moving water, water in reservoirs or groundwater levels (hydrological). The NDMC recommends that decision-makers adopt an operational definition of drought for their own situation and include local data such as grazing conditions or current at a nearby gauge. Drought can have a variety of environmental, social and economic impacts. Here are some examples of the profound consequences of drought. The Dust Bowl era of the 1930s affected 50,000,000 acres of land and left farmers powerless. In the 1950s, the Great Plains suffered from severe water scarcity over the years and much lower than normal rainfall. Crop yields have lagged behind and water supply has declined. California suffered a severe drought around 1970. The amount of precipitation was 1 year and a half below normal, and by September 1970 the fire potential was extremely high and dangerous.

Temperatures reached almost a century and fires broke out. Losses were in the order of a million in double digits. Water allocations for river, wetland, wildlife and fish restoration projects can be reduced or stopped altogether in the event of a severe drought.