Science
Center Pivot Irrigation System in Arizona
The USGS together with partners and stakeholders are working together to understand the complexity of drought impacts and compounding hazards, such as climate change on human and natural systems. Interdisciplinary science evaluates the wide-ranging effects of drought and supports collaboration between stakeholders, scientists, and technology specialists.
Science Topics
FAQs
What causes drought?
A drought is a period of drier-than-normal conditions that results in water-related problems. The amount of precipitation at a particular location varies from year to year, but over a period of years the average amount is fairly constant. In the deserts of the Southwest, the average precipitation is less than 3 inches per year. In contrast, the average precipitation in the Northwest is more than...
When does a drought begin and end?
The beginning of a drought is difficult to determine. Several weeks, months, or even years might pass before people know that a drought is occurring. The end of a drought can occur as gradually as it began. The first evidence of drought is usually seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease. The effects of a drought on flow in...
Where in the Nation are droughts or very low flows occurring now? How can I see these sites on a map and get to the data?
To view the USGS streamflow information on drought, see the drought map on our WaterWatch site, which shows below-normal, 7-day average streamflow compared to historical streamflow for the United States. Links to additional maps and drought data are listed on the USGS Drought website and the National Integrated Drought Information System (NIDIS) .