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St. Petersburg Coastal and Marine Science Center > National Assessment of Storm-Induced Coastal Change Hazards > Hurricane Sandy

National Assessment of Storm-Induced Coastal Change Hazards

Hurricane Sandy

Pre-Storm and Post-Storm 3D Lidar Topography: North Carolina

The USGS conducted an airborne lidar survey of the topography of North Carolina in November 2012, after Hurricane Sandy passed by to the East. In November 2009, the USGS conducted a similar survey after Ida (also known as "Nor'Ida") impacted the Northeast United States. Comparing these two surveys reveals the nature, magnitude, and spatial variability of hurricane-induced coastal changes, such as beach erosion, overwash deposition, and island breaching. At least one other large storm occurred in the period between the two lidar surveys, so these data document the cumulative impacts of these events.

Location Map
North Carolina Index Map. Click on the yellow highlighted numbers to see maps of that location. The numbers correspond to the pre- and post-storm photograph comparisons. In the inset map, the green line is Hurricane Sandy's track and the red line indicates the shoreline where post-storm airborne lidar data were collected after Hurricane Sandy's landfall.

Below are pre-storm elevation maps, post-storm elevation maps, and elevation difference maps at each highlighted location. In the pre- and post-storm elevation maps, orange and red colors indicate higher elevations while yellow and green colors indicate lower elevations. In the elevation difference maps, red colors indicate erosion such as shoreline retreat, and blue-green colors indicate accretion, such as overwash deposits where waves and surge have moved sand landward. The location numbers correspond to the photo pair comparisons. The maps are oriented with the Atlantic Ocean on the bottom.

Location 2

Pre-Storm Elevation
pre-storm elevation for Pea Island National Wildlife Refuge, Kinnakeet, North Carolina

    Post-Storm Elevation
post-storm elevation for Pea Island National Wildlife Refuge, Kinnakeet, North Carolina

Elevation Difference
elevation difference for Pea Island National Wildlife Refuge, Kinnakeet, North Carolina
 
Location 2: Pea Island National Wildlife Refuge, Kinnakeet, NC.
Prior to Hurricane Sandy, the dunes here varied in height and width. During Hurricane Sandy, the lower and narrower dunes were overwashed by the waves and storm surge that carried sand from the beach and dunes and deposited it on the road and marsh in overwash fans.

Location 4

Pre-Storm Elevation
pre-storm elevation for for Rodanthe, North Carolina

    Post-Storm Elevation
post-storm elevation for for Rodanthe, North Carolina

Elevation Difference
elevation difference for Rodanthe, North Carolina
 
Location 4: Rodanthe, NC.
Prior to Hurricane Sandy several houses sat on top of or just seaward of the dunes or highest elevations on this part of the island. The relatively high elevation of the houses has been identified and marked with black shading on the maps. After Sandy, the beach and dunes have eroded and the shoreline has moved landward, leaving some of the houses more vulnerable to future storms. Storm surge and waves produced overwash that deposited sand on the coastal roads.

Note: The results presented here are considered preliminary and have not been thoroughly reviewed or edited. They are based on preliminary data that may be updated as the survey accuracy improves in future processing steps such as application of the precise ephemeris for GPS satellites, offset checks using ground control surveys, checks for laser calibration and mounting errors, and full application of data quality control, assurance and editing procedures.


St. Petersburg Coastal and Marine Science Center > National Assessment of Storm-Induced Coastal Change Hazards > Hurricane Sandy

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Page Last Modified: December 05, 2016 11:24 AM (JSG)

Location 4 Location 2