Hurricane Katrina originated near the Bahamas as Tropical Depression 12 of the active 2005 hurricane season on Tuesday, August 23 ((Knabb, Rhome, & Brown, 2005). It was named Katrina when it developed into a tropical storm the following day. It continued intensifying as it approached the Florida coast. It reached hurricane status two hours before striking land for the first time on August 25 (Knabb, 2005). Its foray over land weakened the storm back down to a tropical storm, but its trajectory took it over the Loop Current in the Gulf of Mexico (Knabb, 2005). The bathtub warm waters intensified it into a category three hurricane. Not only did Katrina intensify, but it also grew to an enormous size, which contributed to its vast potential for destruction. By August 27, Katrina had become category five and seemed to be heading straight towards southeastern Louisiana (Knabb, 2005).

Evacuation and Preparation

By August 26, the probability of Katrina hitting New Orleans directly was 17% (NOAA, 2005). This number rose to 29% by August 28 (NOAA, 2005). Projected storm surge was set at 28 ft (8.5 m) (Drye, 2005). Because of doomsday-like predictions from the Army Corps of Engineers and FEMA in the case of a direct hit from a category three storm, mayor Ray Nagin announced the first mandatory evacuation in the history of the city (FOX, 2005). To help citizens evacuate, the inbound highway lanes of I-10 were turned into additional outbound lanes. This system is called contraflow.

For those who could not leave, the government set up the Louisiana Superdome as a shelter of last resort (FOX, 2005).

Destruction

When Hurricane Katrina came ashore, it hit southeastern Louisiana as a category three storm. It had sustained winds of 125 miles per hour. Because of the storm's size, it subjected New Orleans to hurricane force winds for hours (Knabb, 2005). The massive storm surge caused levee failures in several canals in the city, which allowed tremendous amounts of water to fill the bowl. The 17^th Street Canal experienced a levee breach on its east side, emptying tons upon tons of water into Lakeview district (Murphy, 2005). Arguments continue to rage as to the cause of the breach: either the wall was over topped and its base eroded from dumping water or it slid from beneath as a result of poor base sediment and I-wall design. The Industrial Canal, which runs from Lake Pontchartrain to the Mississippi River also experienced levee breaches, the most notable of which resulted in a barge ending up in the remnants of the Lower Ninth Ward (Murphy, 2005). Speculation remains as to whether the barge caused the breach or whether it was simple over topping from storm surge. The London Avenue Canal also contributed to the disaster by flooding western Gentilly with storm water (Murphy, 2005). Its breach was due to poor engineering. The soil it was constructed on was too loose, which caused the wall to buckle under the strain of increased water pressure. New Orleans East was flooded by breaches in the Mississippi River Gulf Outlet(MR-GO) (Murphy, 2005). The southern half of the district was devastated by the inundations. Outside Orleans parish, St. Bernard and Plaquemines parishes were ravaged by the wind and water from Katrina (Murphy, 2005). High rise buildings received the worst wind damage because the hurricane winds increase greatly with altitude. The Superdome, which housed 26,000 during the storm lost its roof to the winds (Staff Writer, 2005). The situation at the football stadium became a humanitarian crisis when food and water ran out. People died from heat stroke, stress, and dehydration. The Hyatt hotel was reported having lost beds through its windows (Mowbray, 2005).