1. Location index for pre-storm and post-storm LIDAR elevations for the Outer Banks, NC (Location 4 on map). Each location includes pre- and post-storm topography as well as topographic change. The green line shows Hurricane Irene's track.
On the elevation images below, red colors indicate topographic highs, while blues indicate topographic lows. The differences between the pre- and post-storm elevation data sets show where significant changes have occurred. Red colors indicate erosion. For example, oranges and reds on the seaward side of the islands indicate widespread shoreline retreat. (In each image, the Atlantic Ocean is on the bottom right.) Blue colors show areas of accretion, such as overwash deposits where waves and surge have moved sand landward.

2. Before and After Hurricane Irene Aerial Photographs
From

3. November 27-December 1, 2009 (pre-storm) Outer Banks near Rodanthe, NC
Location 4: LIDAR topography from November 27-December 1, 2009 (pre-storm) and August 28-29, 2011 (post-storm) and topographic change (difference) for a portion of the Outer Banks near Rodanthe, NC. “In the pre-storm image, note where the road bends seaward, approaching the Atlantic Ocean. Here, the road is protected by sand-filled bags that appear dune-like in the LIDAR topography. The post-storm image reveals where the waves and surge from Irene broke through the protection and carved a breach. The difference image shows the extensive erosion associated with breach formation.” See pre- and post-storm photo comparisons at [ for additional discussion.
RED = HIGH, BLUE = LOW

4. August 28-29, 2011 (post-storm) for a portion of Outer Banks near Rodanthe, NC
Location 4: LIDAR topography from November 27-December 1, 2009 (pre-storm) and August 28-29, 2011 (post-storm) and topographic change (difference) for a portion of the Outer Banks near Rodanthe, NC. “In the pre-storm image, note where the road bends seaward, approaching the Atlantic Ocean. Here, the road is protected by sand-filled bags that appear dune-like in the LIDAR topography. The post-storm image reveals where the waves and surge from Irene broke through the protection and carved a breach. The difference image shows the extensive erosion associated with breach formation.” See pre- and post-storm photo comparisons at [ for additional discussion.
RED = HIGH, BLUE = LOW

5. RED = EROSION, BLUE = ACCRETION
Topographic change (difference) for a portion of Outer Banks near Rodanthe, NC
Location 4: LIDAR topography from November 27-December 1, 2009 (pre-storm) and August 28-29, 2011 (post-storm) and topographic change (difference) for a portion of the Outer Banks near Rodanthe, NC. “In the pre-storm image, note where the road bends seaward, approaching the Atlantic Ocean. Here, the road is protected by sand-filled bags that appear dune-like in the LIDAR topography. The post-storm image reveals where the waves and surge from Irene broke through the protection and carved a breach. The difference image shows the extensive erosion associated with breach formation.” See pre- and post-storm photo comparisons at [ for additional discussion.
RED = EROSION, BLUE = ACCRETION