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Quantifying coastal change caused by hurricanes is essential in helping communities better plan for such coastal hazards.

Three illustrations looking down on a coastal region show the land elevation change before and after a hurricane.
Digital elevation models (DEMs) for elevation before Hurricane Isaias (November 12, 2019) and after (August 4, 2020) and the difference map showing the change in elevation for North Core Banks in Cape Lookout National Seashore, North Carolina, from November 2019 to August 2020. Image credit: Jin-Si Over, USGS.

Hurricane Isaias unleashed destructive winds, rainfall, and tornados when it made landfall in North Carolina on August 3, 2020, impacting lives, homes, and infrastructure, as well as the coastline and coastal features. Quantifying this coastal change is essential in helping communities better plan for sea-level rise, changing storm patterns, and other coastal change hazards.

USGS uses remote-sensing technologies, such as aerial photography, satellite imagery, and lidar (laser-based surveying), to measure coastal change along U.S. shorelines. Within a few days after Hurricane Isaias, the USGS Remote Sensing Coastal Change (RSCC) project rapidly processed Emergency Response Imagery collected by NOAA’s National Geodetic Survey. The USGS RSCC team used the NOAA imagery to produce digital elevation models (DEMs) and compared them with DEMs made from USGS imagery collected in North Carolina in November 2019. Using these models, RSCC produced difference maps for North Core Banks in Cape Lookout National Seashore to analyze storm-induced coastal change. The results provided the National Park Service with critical information before field-based assessment teams were deployed on the ground, helping them decide how and where to access the island so they could focus on impacted areas of the coastline. Jeff West, the Superintendent at Cape Lookout National Seashore, said, “Our ground observations support the image assessment! The production of the image assessment was quicker than our ability to get out there and look at it on the ground. As you suggest, if we could get the processed data out to us before our assessment teams get on the ground, it would help us focus on impacted areas. And, it could help dictate how and where we access the island. This is great work...”

The change analysis performed by the USGS RSCC team determined that Hurricane Isaias helped some North Core Banks beaches recover from erosion caused by Hurricane Dorian (2019). Specifically, results showed sand overwash (the flow of water and sediment over a dune or beach crest during storm events) in channels previously eroded by Hurricane Dorian and sand deposited at some beaches on North Core Banks.

USGS is dedicated to providing prompt, actionable data and analysis to meet stakeholder needs. The USGS RSCC team has continuously shared knowledge with NOAA’s National Geodetic Survey as an image provider and with stakeholders, such as the National Park Service. Building and maintaining productive partnerships are key in effectively serving U.S. coastal communities.

Visit the USGS Coastal Change Hazards web site to learn more about our related research, technical capabilities and applications, and stakeholder engagement and communications efforts.

Illustrations show elevation of a beach and how sand gets redistributed following a hurricane.
Image showing a detail of one of the washover deposits accumulating in a gully formed by Hurricane Dorian, with cross-section showing accumulation on the beach and at the distal end of the washover deposit. Image credit: Jin-Si Over, USGS.
A pilot of a small plane took this photo from his pilot's seat looking out at a beach with a partial view of the cockpit.
View from the plane over Cape Hatteras, North Carolina, taken in the fall of 2019 on a USGS overflight. Photo credit: Wayne Wright, USGS.


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