Sign up to receive an email update when a new issue of Sound Waves is available.

close window

Link to USGS home page
Sound Waves Monthly Newsletter - Coastal Science and Research News from Across the USGS
Home || Sections: Cover Stories | Fieldwork | Research | Outreach | Meetings | Awards | Staff & Center News | Publications || Archives

 

Cover Story

Before-and-After Photos: SE Beach Dunes Lost to Hurricane Matthew



in this issue:
 next story

Hurricane Matthew’s storm surge and waves overwashed 177 miles of beach dunes in four states—about 11% of the sand dunes on Florida's Atlantic Coast, 30% along Georgia’s coastline, 58% of dunes on South Carolina’s sandy beaches, and 9% of North Carolina's dunes as the powerful storm brushed past the southeastern states October 6–9, 2016. These figures are derived from USGS experts' preliminary review of USGS low-altitude before-and-after images along the coast and NOAA photographs collected after the storm.

“The hurricane's impact on southeastern shorelines was less extensive than a pre-storm prediction, which called for 24% of Florida’s Atlantic Coast to be overwashed by the storm surge,” said USGS research oceanographer Joseph Long. “That forecast was based on a worst-case scenario, the maximum waves forecast by the National Hurricane Center striking the coast simultaneously with the maximum storm surge.”

Long and his fellow scientists on the USGS National Assessment of Coastal Change Hazards storm team, headed by research oceanographer Hilary Stockdon, are working on a detailed assessment of Matthew’s effects on the region’s vulnerable shorelines. They are now comparing low-altitude, oblique aerial photos taken in September 2014 to photos collected October 13–15, about a week after the storm.

Low-altitude oblique photography before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 14, 2016) at Vilano Beach, Florida      Low-altitude oblique photography taken before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 13, 2016) shows the storm cut a new inlet between the Atlantic Ocean and the Matanzas River near St. Augustine, Florida
Above: Low-altitude oblique photography before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 14, 2016) at Vilano Beach, Florida, shows storm surge and wave runup washed away a 5-meter-high (16-foot) sand dune, destroying boardwalks and decks and exposing an old seawall. [larger version]    Above: Low-altitude oblique photography taken before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 13, 2016) shows the storm cut a new inlet between the Atlantic Ocean and the Matanzas River near St. Augustine, Florida, stripping away a 3.7 meter (12-foot) dune and carrying sand into the estuary. [larger version]

“High-altitude images give us a big-picture view of the coastline, and that’s very useful to identify large areas of overwash, but we can’t see the dunes in those images,” Long said. “These low-altitude photos give us a clear view of the dune itself. We can see whether the storm surge altered or eliminated that protective barrier, and what happened to the houses and boardwalks and seawalls behind it.”

When a storm is about to strike the U.S. Atlantic Coast, the team predicts the likelihood of coastal erosion and other changes, using a computer model that incorporates the National Hurricane Center’s storm-surge predictions and NOAA wave forecasts. The USGS model adds information about the beach slope and dune height to predict how high waves and surge will move up the beach.

Low-altitude oblique photography taken before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 13, 2016) in Flagler Beach, Florida
Above: Low-altitude oblique photography taken before Hurricane Matthew (Sept. 6, 2014) and after (Oct. 13, 2016) in Flagler Beach, Florida, shows that waves washed away part of Highway A1A and obliterated a 5.2-meter-high (17-foot) dune. [larger version]

The model forecasts three types of storm impact to the dunes that protect coastal communities: erosion, overtopping, and inundation (flooding that reaches over and behind the dunes). After a storm has passed, the researchers test the model’s accuracy using information about the state of the dunes from before-and-after photographs and other data. 

In Florida, the state that had the closest brush with Matthew, an estimated 64 kilometers (40 miles) worth of dunes and other coastal structures were overtopped. A preliminary review found 52 kilometers (32 miles) worth of shoreline in Georgia and 121 kilometers (75 miles) in South Carolina were overwashed, mostly in lightly populated areas. In North Carolina, the hurricane’s impacts were dominated by heavy rainfall that led to inland flooding, but storm tides also overtopped about 48 kilometers (30 miles) of dunes, according to the team's preliminary analysis.

The images clearly capture the damage at Florida’s Vilano Beach, north of St. Augustine, where the storm surge and wave runup washed away a five-meter-high (16-foot) sand dune, destroying boardwalks and decks of oceanfront homes. South of St. Augustine, the storm surge opened up a new inlet between the Atlantic Ocean and the Matanzas River, stripping away a 3.7-meter-high (12-foot) dune and carrying most of its sand into the estuary. And farther south in the town of Flagler Beach, the powerful waves washed away a portion of Highway A1A, closing the beachfront highway indefinitely, and obliterated a 5.2-meter-high (17-foot) dune.

Low-altitude oblique photography before Hurricane Matthew (Feb. 19, 2016) and after (Oct. 15, 2016) shows storm surge and wave runup eroded dunes and exposed State Road 12 to wave attack, undercutting the roadway at Kitty Hawk, North Carolina      Low-altitude oblique photography before Hurricane Matthew (Sept. 24, 2011) and after (Oct. 14, 2016) at Pritchards Island, South Carolina
Above: Low-altitude oblique photography before Hurricane Matthew (Feb. 19, 2016) and after (Oct. 15, 2016) shows storm surge and wave runup eroded dunes and exposed State Road 12 to wave attack, undercutting the roadway at Kitty Hawk, North Carolina. The yellow arrows in each image point to the same features in both photos. [larger version]    Above: Low-altitude oblique photography before Hurricane Matthew (Sept. 24, 2011) and after (Oct. 14, 2016) at Pritchards Island, South Carolina, shows that in the five years between photographs, the line of vegetation has moved landward as trees exposed to saltwater have died. The lack of vegetation allowed further erosion and overwash during Hurricane Matthew. The yellow arrows in each image point to the same features in both photos. [larger version]

The U.S. Army Corps of Engineers, in collaboration with the USGS, is conducting a month-long series of data collection flights along the southeastern U.S. coast using airborne lidar, a technology that bounces beams of laser light at the ground to produce detailed elevation information about the surface below. Using that information, the USGS researchers can estimate the volume of sand that Hurricane Matthew moved off of southeastern beaches, measure the height and breadth of the remaining dunes, and be ready to forecast the erosion potential of the next storm.

See more before-and-after-Hurricane Matthew photos from Florida through North Carolina at http://coastal.er.usgs.gov/hurricanes/matthew/, and learn more about the USGS coastal change hazard team's hurricane research at http://coastal.er.usgs.gov/hurricanes/.

 

Related Sound Waves Stories
This Hurricane Season, Scientists Bring Wave Action into the Picture
June / July 2016
Hurricane Sandy: Three Years Later
Dec. 2015 / Jan. 2016

Related Websites
Hurricane Matthew Before-and-After Photos
USGS
Hurricane Matthew Oblique Aerial Photography
USGS
Hurricane Matthew
USGS
National Assessment of Coastal Change Hazards
USGS

next story

 

print this issue print this issue

in this issue:

Cover Story
SE Beach Dunes Lost to Hurricane Matthew

News Briefs
News Briefs

Fieldwork
Indian Ocean Gas Hydrates Drilling

Recent Fieldwork

Research
Measuring Coastal Erosion in California

Solid Footing for Offshore Wind Turbines

Outreach
Woods Hole Science Stroll

Awards
James Hein Wins Moore Medal Award

International Recognition for Historic Elwha River Restoration

Meetings
AGU Fall Meeting

International Symposium on Deep-Sea Corals

SACNAS National Conference

Staff
Visiting Scholar Studying Arctic Ocean Ferromanganese Crusts and Nodules

Publications
Structured Decision Making in Barrier Island Restoration

Oct. - Dec. Publications

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://soundwaves.usgs.gov/2016/12/index.html
Page Contact Information: Feedback
Page Last Modified: January 03, 2017 @ 12:15 PM