Drought Terms and Definitions
This list outlines terms commonly used for drought planning and monitoring purposes.
- Drought Indices: Assimilate data on rainfall, snowpack, streamflow, and other water supply measurements into a comprehensible picture of drought development and severity (NDMC website, “What Is Drought: Drought Indices,” Michael Hayes). Some examples of common drought indices are: Palmer Drought Severity Index, Crop Moisture Index, Surface Water Supply Index, and the Standardized Precipitation Index.
- Drought Management Planning: Includes drought mitigation and drought response planning. The main objective of drought management planning is to preserve essential public services and minimize the adverse effects of a water supply emergency on public health and safety, economic activity, environmental resources, and individual lifestyles.
- Drought Mitigation: Refers to actions taken in advance of a drought that reduce potential drought-related impacts when the event occurs. This includes measures taken in advance of a disaster that are aimed at decreasing or eliminating drought impacts on society and the environment.
- Drought Stages: Describe the severity levels of drought and are generally differentiated by pre-defined trigger points or thresholds.
- Drought Types
- Meteorological drought – a period of below-average precipitation.
- Agricultural drought – a period of inadequate water supply to meet the needs of the state’s crops and other agricultural operations such as livestock.
- Hydrological drought – deficiencies in surface and subsurface water supplies. Generally measured as streamflow, snowpack, and as lake, reservoir, and groundwater levels.
- Socioeconomic drought – occurs when drought impacts health, well-being, and quality of life, or when a drought starts to have an adverse economic impact on a region.
- Impact: Measured or observed affect of drought that could include social, economic, and environmental sectors.
- Response Action: Actions that will be carried out during a drought as various drought trigger points are reached. Response strategies can include anything from short-term emergency aid to government assistance programs and media relations.
- Response Planning: Addresses the conditions under which a drought induced water supply shortage occurs and specifies the actions that should be taken in response.
- Risk: A combination of hazard, vulnerability, and exposure. Risk assesses the impact a hazard would have on people, services, facilities, and structures in a community and refers to the likelihood of a hazard event resulting in an adverse condition that causes injury or damage. Vulnerability As defined by FEMA’s risk assessment guidance (FEMA 386-2),
- Vulnerability: Being open to damage or attack. Vulnerability is also defined as the likelihood that an area or sector will be negatively affected by environmental hazards (Bolin and Stanford, 1998).