Three separate downpours in three states over an eight-day period this summer wiped out homes, destroyed crops and killed at least 39 people.
The intense rainfall in Missouri, Kentucky and Illinois broke age-old records and destroyed parts of communities, prompting warnings from climate experts, who said the intensity and frequency of heavy rainfall was likely to increase as the Earth warmed further.
Some areas of southeastern and central Illinois received more rain on Monday and Tuesday than usual throughout August. In eastern Kentucky and central Appalachians, the rainfall observed from July 26 to July 30 was more than 600 percent of normal. In Missouri, rainfall records were wiped out last week during a two-day downpour.
No storm can be directly attributed to climate change without further analysis, but the intensity of these downpours matches how global warming has led to an increase in the frequency of extreme rainfall. A warmer Earth has more water in the atmosphere, resulting in heavier rainfall.
“We expect these kinds of events to become even more frequent or even more extreme in the future as the Earth warms further, meaning this is kind of a call to action that climate change is here,” Kevin says. Reed, an associate professor in the School of Marine and Atmospheric Sciences at Stony Brook University in New York. “It won’t be a problem in 50 years. It’s a problem now.”
‘Historically unprecedented’ amounts of rain.
The pressure on cities and states to prepare for these events was evident in Kentucky, where at least 37 people died, and Missouri, where two people died.
In Kentucky, sometimes more than four inches an hour fell, the National Weather Service said:and wiped out homes and parts of some communities.
In four days, between 14 and 16 inches of rain fell in a narrow swath in the eastern part of the state, according to radar-based estimates from the Weather Service. It said this is “historically unheard of” and that there was a less than 1 in 1000 chance of that much rain falling in any given year.
Earlier that week in eastern Missouri, the Weather Service said 7.68 inches of rain fell in a six-hour period, an event that also had a 0.1 percent chance of occurring in any given year.
That downpour hit the area in and around St. Louis especially hard, forcing residents to flee their homes in inflatable boats after roads flooded with water.
The deluge on July 25 and 26 was the most prolific rainfall in St. Louis since records began in 1874, according to the Weather Service. About 25 percent of the area’s normal annual rainfall fell in about 12 hours.
Neil Fox, a professor of atmospheric sciences at the University of Missouri, said the heavy rainfall in Missouri was caused by thunderstorms that developed over and over in the same area, known by meteorologists as training. Training is a common cause of heavy rainfall and also caused the downpours in Illinois and Kentucky.
“The number of records broken is like someone breaking the world record in the 100 meters by a second or so,” said Professor Fox. “It’s an incredible increase from the previous record.”
Rainfall in Illinois this week was less intense and no deaths were reported, but the Flood caused flash flooding and damaged crops. The Weather Service said the highest rainfall recorded in that storm was seven inches, which has a 1 to 2 percent chance of occurring in any given year.
“We usually get a little over two inches in the month of August, and we got five to seven inches in the first two days here in August,” said Nicole Albano, a meteorologist with the National Weather Service’s office in Lincoln, Illinois. “That’s pretty substantial.”
The United States and other parts of the world have seen an increase in the frequency of extreme rainfall events due to climate change, caused by the burning of fossil fuels such as oil and gas. The frequency of these heavy downpours is likely to increase as warming continues.
“We also expect the heaviest possible precipitation events in a given location to become heavier as temperatures rise,” said Angeline Pendergrass, an assistant professor at Cornell University in Ithaca, NY, who studies extreme precipitation. “That means we should expect more precipitation records to be broken than without global warming.”