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.”