The United States saw 1 in 1,000 years of rain in a week for the third time Monday night and Tuesday morning, as southern Illinois was drenched with 8 to 12 inches of rain in 12 hours. An area just south of Newton, Illinois, registered 14 inches of rain in just 12 hours, according to the National Weather Service. Thunderstorms brought damaging winds and heavy rainfall Tuesday afternoon through mid-afternoon.
Heavy rains like this are becoming more frequent due to climate change.
The NWS office in Lincoln, Illinois, received about 20 flooding reports Tuesday as roads turned into rivers. Several flash flood warnings have been issued in the region.
The extraordinarily heavy rainfall in Illinois follows similar events in Kentucky and Missouri. Record-breaking rainfall caused flash flooding in the St. Louis area last Tuesday, causing cars to get stuck, roads closed and at least one death. Last Thursday, nationwide areas of eastern Kentucky were flooded after receiving up to 14 inches of rain. The capital punishmentstood at 37 at the most recent count.
Although more rain fell in Illinois Tuesday morning — a foot in the area southeast of Springfield, Illinois, for example — flooding was worse in St. Louis because urbanized areas are more heavily paved and less able to absorb water.
All three floods are considered 1,000-year rainfall events because the amount of rain that falls during such a short period of time has only a 0.1% chance of happening in any given year.
But that was before climate change. As a result of rising concentrations of heat-trapping gases, mainly from the combustion of fossil fuels, the global average temperature has risen by 1.1 degrees Celsius since the start of the industrial revolution. With every degree Celsius higher temperature, the air can hold 7% more moisture. Therefore, unusually heavy rains are becoming more frequent and more intense.
This is especially true in the already wet Northeast and Midwest. Last year, the Detroit area received 6 inches of rain in June and 8 inches in August, flooding cellars and cars, and hurricane Ida dumped more than 3 centimeters of rain on New York City in just an hour, resulting in flooding that kills 11 people and close the subway system.
Academic studies have shown that extreme rainfall and flooding will get worse in the future, especially if climate change continues unabated.