Nor'easter Strengthening, Bringing Risk of Heavy Rain and Flooding to East Coast
Climate experts note that while the number of nor'easters may not be increasing, the intense storms are becoming more severe, with higher rainfall totals and stronger winds.
A strengthening nor'easter is poised to bring heavy rain, significant flooding, and powerful wind gusts to millions along the U.S. East Coast this weekend. Coastal areas in Virginia and North Carolina have already experienced flooding, and wind speeds are expected to reach up to 50 mph in some regions.
The storm has the potential to stall off the coast between New Jersey and Long Island, exacerbating conditions and prolonging the impacts. Northern New Jersey, New York City, Long Island, and southern New England are anticipated to face the brunt of the storm, including its strongest winds, heaviest rainfall, and coastal flooding. Precipitation is forecast to begin as early as Friday evening and continue through the weekend.
"This nor'easter is shaping up to be impactful in part because it will be slow moving, potentially building up a large storm surge," said Michael Mann, professor of climate science and climate change at the University of Pennsylvania.
Understanding Nor'easters
Nor'easters, named for the northeasterly winds that characterize them, typically affect the East Coast of the U.S. and Canada, bringing either rain or snow. While they can occur year-round, they are most common between September and April. Similar to hurricanes, nor'easters draw energy from ocean heat. However, they generally possess cold cores and can persist over an area for longer durations than hurricanes.
Historically, nor'easters have caused billions of dollars in damage across the U.S. Notable past events include the New England Blizzard of 1978, the March 1993 "Superstorm," and the Boston snowstorms of January and February 2015.
Climate Change and Nor'easter Intensity
While the precise impact of climate change on nor'easters is still under study, scientists have observed that intense storms are becoming more extreme. "If there’s one thing that’s clear, it’s that the more intense nor’easters are becoming more extreme—bringing with them more rainfall and stronger winds," stated Mathew Barlow, professor of climate science at the University of Massachusetts Lowell. This intensification can lead to increased storm surges, coastal flooding, and wind damage.
"Human-caused warming is leading to higher precipitation totals with these storms," Mann explained. This phenomenon is becoming increasingly common with extreme weather events as a warmer atmosphere holds more moisture, leading to heavier precipitation.
Barlow noted that while not every storm is intensifying, the severe ones are exhibiting greater intensity, whether they be thunderstorms, hurricanes, or nor'easters. He also added that the total number of storms does not appear to be changing significantly, and may even be decreasing slightly.
In a warming climate, the intensity of storms, including rainfall and wind speeds, is expected to continue increasing. Climate change is also contributing to a rise in "billion dollar disasters" in the U.S., with the time between such events decreasing significantly. "Until we stop increasing the amount of greenhouse gasses in the atmosphere, the intensity of rainfall, the intensity of these storms, will continue to increase as well," Barlow warned. "Until we stop making things worse, things are going to keep getting worse."