South Carolina’s catastrophic 1,000-year rainfall event

The meteorology behind South Carolina’s catastrophic, 1,000-year rainfall event

The rains are tapering off in South Carolina after a disastrous weekend that brought over two feet of rain and catastrophic flooding. Dams have been breached, rivers are at record flood stage, homes and cars are filled with water and multiple people have been reported dead in the disaster.

Authorities in South Carolina on Monday urged people to stay home if it was safe to do so, saying that flooding was expected to continue in more than half the state for several days. On Sunday, authorities responded to hundreds of reports of trees in roadways and hundreds of reports of flooded roads. Tens of thousands of sandbags were used by state and local agencies, while a stretch of Interstate 95 was shut down and traffic rerouted. Overnight, several cities and counties declared curfews, while others have declared states of emergency.

According to statistics compiled by the National Oceanic and Atmospheric Administration, South Carolina’s torrential weekend rain has well surpassed a 1,000-year rainfall event — one that, on average, we would expect to see about every 1,000 years. A three-day, 1,000-year rainfall event for Charleston County would have been 17.1 inches. A four-day, 1,000-year event would have been 17.5 inches. Boones Farm Plantation, just north of Mount Pleasant, in Charleston County, reported more than 24 inches of rain through Sunday morning, which essentially blows NOAA’s 1,000-year events scale out of the water