Flash Drought in the South Brings Record Heat Without Rain

It was a hot summer in the American South, and droughts have affected tens of millions of people there after one of the driest and hottest Septembers on record.

Because this dry spell began quickly — instead of creeping in gradually, as droughts usually do — it’s being referred to as a “flash drought.”

In other words, “some of these areas have basically seen the faucet turn off,” said Brian Fuchs, a climatologist at the National Drought Mitigation Center at the University of Nebraska-Lincoln.

“Then you couple that with well-above-normal, record-setting heat for this time of year,” he added. “Lots of places saw not only the driest September on record, but they also had their warmest temperatures on record.”

Recent news reports about the flash drought have cited the United States Drought Monitor, a map and summary released every Thursday. The project is a collaboration between the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture and the National Oceanic and Atmospheric Administration.

The monitor does not use the term “flash drought” in its summary this week (though government entities have used it elsewhere). It does say “rapidly developing drought,” which basically means the same thing, said Mr. Fuchs, an author of the summary.

The term refers to a sudden onset of low precipitation. While much of the Southeast had normal rainfall levels in early summer, the rain began to dry up about 10 weeks ago, the summary said.

It added that temperatures had soared in the eastern two-thirds of the country — sometimes up to 15 degrees higher than normal.

The map highlighted drought conditions across much of the South, from Arizona all the way east through Virginia, with some bright red spots of extreme drought in Kentucky, South Carolina, Georgia, Alabama, Texas and northern Florida.

In the Southeast, “the warm and dry pattern continued over the region, with temperatures for the week generally 9 to 12 degrees above normal,” the report said. “Most of the region was dry with only small, isolated pockets of observed precipitation.”

“Very dry conditions also dominated regions in the southern Plains, southern Midwest and along most of the East Coast,” it added. “The heat and dryness have continued setting the stage for rapidly developing drought.”

“With a short-term drought like this, the impacts that we’re seeing right now have mainly been in the agricultural sectors,” Mr. Fuchs said.

In Cumming, Ga., which is just northeast of Atlanta, it’s about 10 degrees warmer than normal for this time of year, and some farmers’ crops are suffering from the heat, said Stephen Daniels, who manages The Cumming Harvest, a farmer’s market there.

Cumming was stained bright crimson on the Drought Monitor map, denoting an area of extreme drought. The high temperature for Friday was in the mid-90s.

“They call it ‘Hotlanta’ for a reason, so it’s not like this is the first time it’s been 90,” Mr. Daniels, 63, said. “But this is a long dry spell, so maybe it’s a little bit harder than normal.”

It’s hot in Texas, too, said John Nielsen-Gammon, the state climatologist there and a professor of atmospheric sciences at Texas A&M University. He said drought conditions were particularly hard on crops, livestock and water levels.

The relationship between global warming and individual weather events is complex.

Regarding this drought, “the only thing that can be conclusively said to be related to climate change is the high temperatures, just because temperatures were warmer by about 1 or 2 degrees already, compared to what they were the last century,” Dr. Nielsen-Gammon said. “With the rainfall levels, there are competing influences.”

Generally speaking, global warming is making heat waves longer and more frequent. But it is also increasing the frequency and intensity of heavy rainstorms.

“It’s hard to attribute any single event to climate change,” Mr. Fuchs said. “Is it contributing? Yes. And I think where we’re seeing it contribute is this persistent heat, late summer into early fall.”

Temperatures will cool as the days go on, but the dry conditions could persist awhile.

“That outlook for October is still showing that the majority of the region is going to stay in drought or even see further development” of drought conditions, Mr. Fuchs said.

But he added that tropical weather events — such as depressions and storms — may bring some rain. “That’s really the wild card,” he said.

In the meantime, people should hydrate, stay cool and be on the lookout for fires, which can ignite more easily in dry conditions like these.