Changes between the pre- and post-Ivan lidar surveys draped over topography: The topographic surveys shown at the top of this page have been differenced to show vertical change; red indicates a decrease in elevation and green indicates an increase. This vertical change has been draped over the post-Ivan topography. The houses that survived the storm are white, indicating no change. The houses that were destroyed are red, indicating loss of elevation. Note the green area over the center section of road indicating that sand has been deposited by wave overwash.
Before and after Ivan photographs of the area within the rectangle drawn on the lidar images above. These are U.S. Geological Survey photographs. [larger version]