Capt. Paul Carey of the Maryland Natural Resources police shows a side-scan sonar being used in a search on the Chesapeake Bay in 2006. In recent years, the cost of such equipment has come down, allowing more local law enforcement departments to purchase it. Chris Gardener/AP hide caption

itoggle caption Chris Gardener/AP

Floodwaters from Superstorm Sandy destroyed the first floor of this house in Staten Island, New York. Most of the people who drowned during the storm died in their homes in low-lying areas of New York and New Jersey. Paul J. Richards/AFP/Getty Images hide caption

itoggle caption Paul J. Richards/AFP/Getty Images