Fivefold increase of extreme rainfall in US likely

Fivefold increase of extreme rainfall in US likely

By Elisa Jiménez Alonso

Adding to the bleak forecasts for the US is a National Center for Atmospheric Research(NCAR) research paper recently published in Nature Climate Change, which finds that the occurence of extreme summertime rainfall could increase by 400% in parts of the country.

The NCAR scientists also found a potential increase in the intensity of individual extreme rainfall events of 70% in some areas.

Andreas Prein, lead author of the study and NCAR scientist, said “These are huge increases. Imagine the most intense thunderstorm you typically experience in a single season. Our study finds that, in the future, parts of the U.S. could expect to experience five of those storms in a season, each with an intensity as strong or stronger than current storms.”

Extreme precipitation poses a significant risk to people and infrastructure. It can cause flooding, landslides and debris flows.

Image: The figure shows the expected increase in the number of summertime storms that produce extreme precipitation at century’s end compared to the period 2000 – 2013. ©UCAR, Courtesy Andreas Prein, NCAR.

The increase is also expected in areas that are on average getting drier, like the Midwest. This might sound like a contradiction but isn’t. The most important source of moisture is moderate rainfall during which the ground has time to absorb the water. Extreme rainfall in dry areas is more likely to lead to flash floods and mudslides.

The research gives an important glimpse into the future, especially given the potentially very problematic impacts on the infrastructure and populations of affected regions.

Download the report by clicking here (paywall). 

Cover photo by Unsplash/Pixabay (public domain)

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