Blitz Bureau
In two places on the same night, the storm that deluged the Northeast this weekend dumped rain at or near rates that should be expected only once in a thousand years. The storm killed at least three people and caused widespread flooding. It dropped about 10 inches of rain over 12 hours on August 18 in parts of Connecticut including Oxford and Southbury.
Record rain
About 35 miles away, about 6.7 inches of rain fell in three hours the same night in Stony Brook, New York. Both are measures that would have roughly a 0.1% chance of happening in a year, according to federal rainfall probability data.
“There were two areas that got sort of equally extreme rainfall, and they didn’t happen at the same time,” said Nick Bassill, director of the state weather risk communication center at the University of Albany in New York. “Any one of those would be noteworthy, and it’s interesting not only that we got two of them in the larger storm pattern, but that they were consecutive.” It’s impossible to immediately determine the influence of climate change on a particular event, but scientists said the one-two punch of extreme rainfall fits the pattern in the Northeast, where more severe storms are growing increasingly likely.
“These thunderstorms now are packing more rainfall,” said Mark Wysocki, who recently retired as New York state’s climatologist. For every degree of warming in Fahrenheit, the atmosphere can hold about 3% to 4% more moisture. In 2023, global temperatures were roughly 2.4 degrees F higher than they were in preindustrial times, meaning today’s storms can deliver a stronger punch.
Extreme precipitation events Indeed, extreme precipitation events have increased significantly in the Northeast. The 2023 National Climate Assessment found that days with 3 inches of precipitation or more went up about 62% from 1958 to 2018. The number of days with at least 5 inches of precipitation more than doubled during that period.
