Storm-lashed South Carolina reassesses global warming’s role
COLUMBIA, S.C. — When he took the job 15 years ago, Horry County Emergency Manager Randy Webster figured his biggest disasters would be wind and surge rolling over his county’s beaches, South Carolina’s top tourist destination.
Instead, his worries have shifted inland, where rivers overflowing their banks have caused two massive floods in three years.
“We’re getting into this sort of unknown territory,” Webster said. “We typically in emergency management have some point of reference to work with. Two floods like this — it’s unheard of.”
Scientists say the Earth’s warming climate means more heavy rainfall over short periods of time, and that translates to larger, more ferocious storms on the scale of 2017’s Hurricane Harvey in Texas or 2018’s Hurricane Florence in the Carolinas. Florence dumped six months’ worth of rain on the Carolinas in the course of just a few days.
The growing realization that such events are going to become more common as the result of global warming is forcing Webster and other state officials to revisit how they prepare for and respond to natural disasters.
Late last year, Republican Gov. Henry McMaster created the South Carolina Floodwater Commission to figure out how to better combat flooding unleashed by hurricanes, rising ocean levels and other rain systems upstream that send rivers and creeks over their banks on the way to the Atlantic Ocean.
One thing that local governments must do is use forecast tools that predict several different scenarios based on possible temperature rise, rather than relying on flood maps of the past, when severe inundations were rare, said Larry Larson, a former director and senior policy adviser for the Association of State Floodplain Managers.
They also should be prepared to alter landscapes, divert runoff, and to buy up houses and other private properties that frequently end up under water, and to elevate those buildings if necessary, Larson said.
“These owners won’t sell after the first flood; they think they have another 99 years to go,” he said. “But they will sell after the second flood.”
Property owners are resistant because of the cues they get from weather forecasters and government officials, who still employ such terminology as “100year” floods. Despite its name, a 100-year flood doesn’t mean once-in-alifetime. Instead, it means a level of flooding that has a 1 percent chance of happening in any particular year, said Susan L. Cutter, director of the Hazards and Vulnerability Research Institute at the University of South Carolina.
“People are not really good at understanding probability,” Cutter said.
Dealing with the consequences of natural disasters is daunting even when residents receive advance notice. Emergency officials in Conway, a city of 23,000 about 15 miles (24 kilometers) from the beach, took the map of Hurricane Matthew’s flooding in 2016 and — based on forecasts — drew the lines out a little farther, accurately predicting nearly to a home which ones would flood during Hurricane Florence in September. That gave residents a week or more to get whatever they could out their homes.