Climate Matters: Flash droughts are becoming more common with climate change
Drought has spread rapidly across Missouri in recent months, now covering over half of the state as fall gets underway.
It was a much different picture just two months ago, when the region was fully drought-free for the first time in years in late July. Then came a record-dry August and a drier-than-normal September, which resulted in a quick resurgence of drought.
Experts say flash droughts like this are becoming more common in a changing climate. Like a flash flood, a flash drought occurs very quickly, making preparations and planning more difficult.
Drought is typically a long-term event that results from rain deficits over an extended time. But flash droughts can occur when precipitation remains low for just several weeks.
Missouri State Climatologist Zachary Leasor says these rapid changes between wet and dry extremes could become more likely as the climate changes.
"One thing we're looking at in a warming climate would be the potential for more rapid transitions between the extremes, from drought to flood," Leasor says.
The interplay between drought and climate change is complex, with many overlapping variables. Leasor says that while precipitation is an important aspect of drought, so are temperatures.
"With increased temperatures, it really exacerbates the hydrologic cycle," Leasor says, "We can see more atmospheric demand for water." As temperatures warm with climate change, the demand for water also grows.
This contributes to a vicious cycle of worsening droughts and increasing water demand as temperatures continue to rise. "That increases evaporation and water use by plants with those higher temperatures. And so we can be prone to drying out more quickly during those warmer conditions as well." Leasor says.
The rest of the year doesn't look promising, as seasonal outlooks through December indicate warmer and drier than normal conditions across much of the central U.S.
On Tuesday, Governor Mike Kehoe signed an executive order declaring a drought alert in Missouri through the beginning of December. This order will allow state agencies to direct more resources to those affected by the ongoing drought.
