The berm of dunes was swept away across the entire five miles of Folly Beach during Hurricane Matthew. At Edisto Beach the sand was pushed across Palmetto Boulevard.

More than half the dunes bolstering the South Carolina coast were overwashed during Hurricane Matthew, a U.S. Geological Survey aerial study has concluded. Overall, waves swept across 177 miles of dunes from Florida to North Carolina as the storm surge rose as high as 9 feet in spots.

"The beach erosion certainly was prevalent," said Joseph Long, research oceanographer. But the damage in South Carolina wasn't as bad as expected. The survey predicted 70 percent of the dunes would be overrun, he said.

The damage here contrasted sharply with Florida, where stretches of beach were left no more than a hard edge of scarp and the erosion was characterized as extensive, or Georgia, where beaches were lost to the marsh behind. 

The study will be coupled with a U.S. Army Corps of Engineers' regional Lidar survey, which uses remote light detection and ranging to measure beach elevations. The aim is to improve computer modeling for storm surges and give at least some beach managers a better read on what portions of their beachfronts are the most vulnerable.

In the Lowcountry, though, there's not much more to be told. Army Corps engineers with the Charleston District already have had a look at the Lidar results and found they were the same as those concluded measuring from ATVs on the beach, said Wes Wilson, project manager.

The Lidar survey will be ongoing, conducted every few years, said Jackie Keiser, who directs beach sediment management at the Army Corps' regional center. It's designed to be a quicker, more economical and comprehensive study than the local surveys, providing region-wide assessments of beach erosion and accretion.  

The lesson from this round is the expected one: Be prepared, Long said. The results show what can happen to a coastline during a storm.

Reach Bo Petersen Reporter at Facebook, @bopete on Twitter or 1-843-937-5744.

Science and environment reporter. Author of Washing Our Hands in the Clouds.