two-part storm surge. The first surge came as Lake Pontchartrain rose and the storm blew water from the Gulf of Mexico into the lake. The second came as the eye of Katrina passed, westerly winds pushed water into a bottleneck at the Rigolets Pass, forcing it farther inland. The range of surge levels in eastern St. Tammany Parish is estimated at , not including wave action. Hard-hit St. Bernard Parish was flooded because of breaching of the levees that contained a navigation channel called the Mississippi River Gulf Outlet (MR-GO) and the breach of the 40 Arpent canal levee that was designed and built by the Orleans Levee Board. The search for the missing was undertaken by the St. Bernard Fire Department because of the assets of the United States Coast Guard being diverted to New Orleans. In the months after the storm, many of the missing were tracked down by searching flooded homes, tracking credit card records, and visiting homes of family and relatives. According to the U.S. Dept. of Housing and Urban Development, in St. Bernard Parish, 81% (20,229) of the housing units were damaged. In St. Tammany Parish, 70% (48,792) were damaged and in Plaquemines Parish 80% (7,212) were damaged. In addition, the combined effect of Hurricanes Katrina and Rita was the destruction of an estimated of coastal wetlands in Louisiana. New Orleans As the eye of Hurricane Katrina swept to the northeast, it subjected the city to hurricane conditions for hours. Although power failures prevented accurate measurement of wind speeds in New Orleans, there were a few measurements of hurricane-force winds; based on this information, the NHC concluded that much of the city likely experienced sustained winds of Category 1 or 2 hurricane strength. Katrina's storm surge caused 53 levee breaches in the federally built levee system protecting metro New Orleans and the failure of the 40 Arpent Canal levee. Failures occurred in New Orleans and surrounding communities, especially St. Bernard Parish. The Mississippi River Gulf Outlet (MR-GO) breached its levees in approximately 20 places, flooding much of eastern New Orleans, most of St. Bernard Parish and the East Bank of Plaquemines Parish. The major levee breaches in the city included breaches at the 17th Street Canal levee, the London Avenue Canal, and the wide, navigable Industrial Canal, which left approximately 80% of the city flooded. Most of the major roads traveling into and out of