Published on 08/25/99

Drought Among State's Worst Ever in August

After more than six weeks of temperatures in the 90s and low 100s with very little rain, many Georgians are asking, "How dry is it?"

pdsi824.gif (8164 bytes)The Aug. 21 statewide Palmer Drought Severity Index value was -2.7. This means that the state as a whole is classified as being in moderate drought. A statewide PDSI value of -3 would classify Georgia as being in severe drought. Across the state, drought conditions range from mild to severe.

A historical perspective adds more meaning to the PDSI. The statewide value of -2.7 is at the 2nd percentile for the third week in August.

This means that in 98 out of 100 years, the statewide PDSI value for the third week in August would be higher, or less dry. In short, Georgia is having one of the worst August droughts on record.

The PDSI is a long-term drought indicator and responds slowly to recent weather. Statewide PDSI values are available back to 1895.

August 1998 through July 1999 was the 12th driest statewide August-through-July since 1895. July 1999 was the 24th driest since 1895.

How Hot Is It?

Another common question among Georgians is "How hot is it?" In July, statewide average temperature was above normal. But it was only the 60th warmest statewide July since 1895.

The statewide average for May through July was actually below normal. The period ranked as only the 25th warmest May-through-July since 1895. However, because of a very warm winter, the average statewide for August 1998 through July 1999 was the 98th warmest since 1895.

Stream Flow Rates a Concern

The drought is having different impacts across the state. As of Aug. 23, the flow in many rivers and creeks was in the bottom 10th percentile.

Low flow rates and water table levels are becoming a concern statewide. Outdoor watering bans are common across the state.

Short-term Relief

Scattered rain Aug. 23-24 brought short-term relief to many parts of the state. But this rain won't break the drought. Most of the state needs more than half a foot of rain to end the drought. Northeast Georgia needs more than a foot.

As of Aug. 21, the PDSI classifies northeast, west central, southwest and southeast Georgia as being in severe drought.

North central, central, east central and south central Georgia are in moderate drought. Northwest Georgia is in mild drought.

Soil Moisture Short

The Georgia Agricultural Statistics Service reports that moisture is short to very short in 81 percent of the state's soils. This is unchanged from a week earlier. The 81 percent compares to 28 percent last year and 41 percent for the five-year average.

GASS reports that more than 50 percent of the state's pastures are poor to very poor. Some farmers are doing supplemental feeding and culling herds. The hot weather has stressed dairy cattle.

cropmoist824.gif (8556 bytes)The Crop Moisture Index is a measure of soil moisture available for use by crops.

The Aug. 21 CMI indicates that southwest Georgia is extremely dry, with dryland crops in danger of being ruined. West central Georgia is severely dry, with potential yields severely cut.

Excessively dry soils reduce yield prospects in northwest and northeast Georgia. And abnormally dry soils are hurting yield prospects in central, east central and southeast Georgia.

The CMI indicates that soil moisture is short in north central and south central Georgia.

Drought Links

PDSI and CMI values and rankings are calculated by Climate Prediction Center of the National Oceanic and Atmospheric Administration.

You can get updates on drought conditions in Georgia and across the Southeast at the University of Georgia drought Web site. Or call your county Extension Service agent.

Get updated weather data at the Georgia Automated Environmental Monitoring Web site.

David Emory Stooksbury is associate professor of Biological and Agricultural Engineering at University of Georgia's College of Agricultural and Environmental Sciences.