Extreme precipitation events are among the most damaging natural disasters and a major concern in our changing climate.
Extreme precipitation events are among the most damaging natural disasters and a major concern in our changing climate. In the U.S., since 1980, the most destructive events alone have caused over 2800 deaths and $700 billion in damages. But what is the total area of the country affected by these events each year? And how have these patterns changed over the last several decades? In a recent study in Geophysical Research Letters, led by researchers at Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School, the authors discovered some unexpected trends.
Extreme rainfall events that cover large areas, including hurricanes, atmospheric rivers and thunderstorm complexes, are a growing threat, but many studies on extreme precipitation focus on the statistics of rainfall recorded at individual locations, like weather stations. This new study takes a slightly different approach, looking at not only when heavy rainfall events occur, but also how much nearby area was affected by the same event on the same day. For example, a small-area extreme rainfall event may result in a localized flash flood in just a few towns, but large-area extreme events like Hurricane Ida in 2021 can easily cause destruction across entire states at once. Looking at the statistics of extreme precipitation events across both space and time has yielded some surprising results. For example, the average weather station in the eastern half of the U.S. is recording an increasing number of days with extreme rainfall since 1980; at the same time, we are also observing that extreme rainfall events might be decreasing in frequency. How can both findings be true?
Read More: Columbia Climate School
Flooding from excessive rainfall associated with the remnants of Hurricane Ida in the Appalachian region of Pennsylvania near Needmore, PA, September 2021. (Photo Credit: Victor Cortes, USGS)
