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Drought Information

Summaries of Drought Indicators - click on maps to view detailed information from partner agencies.

Skip to Drought Status Reports

U.S. Drought Monitor

The Drought Monitor provides a weekly overview of where in the United States drought is emerging, lingering, subsiding or forecast. The Monitor is produced jointly by the National Weather Service's Climate Prediction Center, the U.S. Department of Agriculture, and the National Drought Mitigation Center at the University of Nebraska-Lincoln.

The three-way partnership is responding to the need for accurate, centralized drought information by developing a map that summarizes information from numerous drought indices and indicators on a single, easy-to-read color map.

 

 

United States Geological Survey (USGS) - Ground Water Climate Response Network

The USGS maintains a network of wells to monitor the effects of droughts and other climate variability on ground-water levels. The network consists of a national network of about 140 wells monitored as part of the Ground-Water Resources Program, supplemented by wells in some States monitored as part of the Cooperative Water Program.

Virginia currently has 20 wells monitored in real-time as part of the Virginia Climate Response Network through a partnership between the USGS and Virginia DEQ.

The data used to produce this map are provisional and have not been reviewed or edited. They may be subject to significant change.

Virginia Climate Response Network

Explanation of symbols on the state map.

United States Geological Survey - Waterwatch

The map depicts streamflow conditions as computed at USGS gaging stations. The colors represent real-time streamflow compared to percentiles of historical daily streamflow for the day of the year. This map represents conditions relative to those that have historically occurred at this time of year.

The "Real-time streamflow" map tracks short-term changes (over several hours) in rivers and streams. Although the general appearance of the map changes very little from one hour to the next, individual sites may change rapidly in response to major rain events or to reservoir releases.

The data used to produce this map are provisional and have not been reviewed or edited. They may be subject to significant change.

Map of real-time streamflow - Virginia

color codes for map

Explanation - Percentile class
color code for new record low
color code for less than 10th percentile
color code for 10th - 24th percentile
color code for 25th to 75th percentile
color code for 76th - 90th percentile
color code for greater than 90th percentile
color code for new record high
not ranked
Low
< 10
10 - 24
25 - 75
76 - 90
> 90
High
Not ranked

Virginia State Climatology Office - Precipitation Deficits

Preliminary Precipitation Summary 11/25/2008 (PDF)

The Virginia State Climatology Office produces precipitation deficits by comparing current precipitation amounts with historical precipitation values as a percent of normal long-term average values.  Comparisons are made for each drought evaluation region.  Normal long-term average precipitation is defined as the mean precipitation for a thirty-year period of record for the area and time period being evaluated.

Precipitation amounts are evaluated based on the water year (beginning October 1).  Water years are natural dividing points for water supply drought as precipitation that falls in the first six months of a water year is analogous to putting money in the bank.  Precipitation that occurs during this six month period has the potential to recharge ground water, which will sustain stream flows and support withdrawals from wells during the following six month period when moisture deficits naturally develop as evaporation and plant transpiration generally exceed precipitation.

Drought evaluation regions

Drought Status Reports (PDF)

Partners

Web resources

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