As the storm from Hurricane Helene swept into North Carolina, David Easterling went into his backyard, just outside of Asheville, to check the rain gauge.
“To walk out and see it almost full was incredible,” he says. “It just rained and rained and rained. It was mind-boggling to see that much rain.”
Easterling is quite possibly the least likely person to be surprised by this. He’s spent more than 30 years studying extreme rain, as a climate scientist at the National Oceanic and Atmospheric Administration (NOAA). Asheville is home to a number of climate researchers who work at the agency’s National Centers for Environmental Information, the central repository for weather and climate data.
Easterling and his colleagues have published some of the most definitive studies showing that rainfall is becoming increasingly intense in a hotter climate. So, the storm’s forecast for more than 15 inches of rain made sense on paper.
“But it just didn’t really, even with me, really click about what that's really going to mean,” he says. “Probably, like anybody else, I was a little complacent about it.”
The storm brought widespread destruction across Easterling’s community. Soils were already saturated before Hurricane Helene’s remnants came through and dropped 20 inches of rain in some places, which caused heavy runoff to fill streams and tributaries. The river swelled, demolishing buildings and destroying vital roads and highways. Easterling’s house is okay, but he worries about neighbors living in more remote valleys.
“All the roads are washed out, they don’t have cell service and there’s no telling how many people have died in those places, " Easterling says. “It’s heartbreaking.”
Easterling says he and colleagues have started crunching the numbers and are finding that North Carolina likely exceeded a 1-in-1,000 year rainfall event. That’s a storm that has a 0.1 percent chance of happening every year. Still, that doesn’t mean it won’t happen again soon.
In much of the country, extreme storms are dropping even more rain. The planet is getting warmer as humans emit more heat-trapping pollution, largely from burning fossil fuels. A warmer atmosphere can hold more moisture, and that fuels more intense downpours.
“A lot of people don’t want to hear global warming and climate change and all that, but this is just a classic sort of event that we, sadly, probably expect to see more of in the future,” Easterling says.
The southeastern U.S. in particular is seeing the impact of heavier rain. Easterling’s research shows that since 1958, the most extreme storms in the region are dropping 37 percent more precipitation. If the climate continues to warm, Appalachia could see extreme storms that are 30 percent worse.
The infrastructure in most communities, including roads, bridges and stormwater systems, is still largely designed for how storms used to be. Many cities are using outdated rainfall records, sometimes decades old, to figure out how much water their infrastructure should be able to handle. That means projects being built today are already inadequate for the storms they’re experiencing.
After a new federal law was passed, NOAA is currently updating the rainfall records nationwide and will include projections of how climate change will make rain heavier. Those are expected to be released in 2026 and 2027. In the meantime, North Carolina and five other states in the region requested that NOAA update their current rainfall records, which is expected at the end of 2025. That data could be vital to communities looking to rebuild and reduce the risk of future flooding.
“The bottom line is: you gotta start planning for these kinds of events,” Easterling says. “Civil engineers need to be taking a hard look at what happened here.”
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