The record rainfalls intensified thanks to a warming climate, experts say.

By Elena Gooray

Vance Barden, right, and Wayne Edwards on a flooded street caused by remnants of Hurricane Matthew in Fair Bluff, North Carolina. (Photo: Sean Rayford/Getty Images)

The storm swept in by Hurricane Matthew has produced rainfall that exceeds the level expected about once every 1,000 years, according to a statistical analysis using National Oceanic and Atmospheric Administration data. Matthew broke numerous rainfall records in some of North Carolina’s toughest-hit towns, marking another spike in this year’s extreme weather. The new rainfall records were enabled by warming in the ocean and coastal atmospheres, which hold more water as temperatures increase — with a few cities across the Southeast reporting record levels of air moisture during the storm.

After devastating the Caribbean, and leading to at least 1,000 deaths in Haiti, Matthew came ashore Saturday in the Carolinas. President Barack Obamasigned a disaster declaration Monday for North Carolina and did the same for South Carolina yesterday. Matthew’s toll is still rising: American deaths from Matthew climbed yesterday to 21, with damages totaling at least $4 billion.

But the most staggering rainfall landed in North Carolina. There, water levels are still rising as the massive pulse of rainwater makes its way to the ocean. At least three rivers have hit, or are expected to hit, record flood stage, inundating countless homes and cutting off roads in one of the poorest parts of the state. In Lumberton, near the heart of the flooding, the water level was up to the rooftops of houses. The New York Times reports that the flooding threatens to kneecap struggling communities, and as with August’s floods in Louisiana, the Washington Post reports that many of those forced out of their homes couldn’t afford flood insurance.

The flooding threatens to kneecap struggling communities.

The flood was also likely made worse by climate change. The 14 inches that accumulated in Fayetteville on Saturday is more than 90 percent likely to fall outside the town’s 1,000-year rainfall return period for a 24-hour rainstorm, and it more than doubled the previous single-day record of 6.80 inches from 1999’s Hurricane Floyd. In fact, only four whole months in Fayetteville’s recorded weather history have seen over 14 inches of total rainfall, Weather Underground has reported. At least two other spots in North Carolina broke the 90 percent confidence intervals for 1,000-year storms: Elizabethtown, with a reported 18.38 inches, and William O. Huske Lock, with 15.65.

Matthew has extended a growing trend of minimum-500-year rainfall events across America, as Eric Holthaus reported for Pacific Standardin August, following Louisiana’s historic storm:

Today’s rainstorm in Louisiana is at least the eighth 500-year rainfall event across America in little more than a year, including similarly extreme downpours in Oklahoma last May, central Texas (twice: last May and last October), South Carolina last October, northern Louisiana this March, West Virginia in June, and Maryland last month.

While the hurricane itself wasn’t necessarily strengthened by climate change, the storm it caused was. “Matthew no doubt rained more than an identical storm would have 30 or 40 years ago because it is warmer,” Kerry Emmanuel, a meteorologist at the Massachusetts Institute of Technology, told the Associated Press. Such events’ increased likelihood is transforming extreme cases closer to something like the norm. As the devastation in North Carolina shows, however, the consequences are anything but normal.

Additional reporting by Eric Holthaus.