When it hit the United States as a post-tropical cyclone, Sandy had a diameter of 1,100 miles and had been the largest Atlantic hurricane on record. It affected 24 states, including the entire Eastern Seaboard from Florida to Maine, causing particularly severe damage in New Jersey and New York. It clobbered the boarded-up big cities of the Northeast Corridor—including Washington, Baltimore, Philadelphia, New York, and Boston—with stinging rain and gusts more than 85 miles per hour. Storm surges, made worse by the full moon, caused high tides to rise about 20% higher than normal.
In the wake of the devastation wreaked by Sandy, dozens of federal, state, and local agencies, as well as many private companies, contributed to the response. Among others, the National Geodetic Survey (NGS) took aerial imagery of the damage, ImageCat helped to analyze the data, Pictometry took oblique imagery, Woolpert flew lidar, and Esri helped FEMA set up a geoportal.