Here is my Third entry:
Hurricane Katrina (2005)

Hurricane Katrina was the costliest and one of the deadliest hurricanes in the history of the United States. It was the sixth-strongest Atlantic hurricane ever recorded and the third-strongest hurricane on record that made landfall in the United States. Katrina formed on August 23 during the 2005 Atlantic hurricane season and caused devastation along much of the north-central Gulf Coast of the United States. The most severe loss of life and property damage occured in New Orleans, which flooded as the levee system built by the US Corps of Engineers failed catastrophically, in many cases hours after the storm had moved inland.[1] The hurricane caused severe destruction across the entire Mississippi coast and into Alabama, as far as 100 miles (160 km) from the storm's center. Katrina was the eleventh tropical storm, fifth hurricane, third major hurricane, and second Category 5 hurricane of the 2005 Atlantic season.

It formed over the Bahamas on August 23, 2005, and crossed southern Florida as a moderate Category 1 hurricane, causing some deaths and flooding there, before strengthening rapidly in the Gulf of Mexico and becoming one of the strongest hurricanes on record while at sea. The storm weakened before making its second and third landfalls as a Category 3 storm on the morning of August 29 in southeast Louisiana and at the Louisiana/Mississippi state line, respectively.

Figure 1: The Track of Hurricane Katrina

Hurricane Katrina formed as Tropical Depression Twelve over the southeastern Bahamas on August 23, 2005 as the result of an interaction of a tropical wave and the remains of Tropical Depression Ten. The system was upgraded to tropical storm status on the morning of August 24 and at this point, the storm was given the name Katrina. The tropical storm continued to move towards Florida, and became a hurricane only two hours before it made landfall between Hallandale Beach and Aventura, Florida on the morning of August 25. The storm weakened over land, but it regained hurricane status about one hour after entering the Gulf of Mexico.

The storm rapidly intensified after entering the Gulf, partly because of the storm's movement over the warm waters of the Loop Current.[3] On August 27, the storm reached Category 3 intensity on the Saffir-Simpson Hurricane Scale, becoming the third major hurricane of the season. An eyewall replacement cycle disrupted the intensification, but caused the storm to nearly double in size. Katrina again rapidly intensified, attaining Category 5 status on the morning of August 28 and reached its peak strength at 1:00 p.m. CDT that day, with maximum sustained winds of 175 mph (280 km/h) and a minimum central pressure of 902 mbar.

Figure 2: Hurricane Katrina at peak strength (152 knots, 902 hPa)

Katrina made its second landfall at 6:10 a.m. CDT on August 29 as a Category 3 hurricane with sustained winds of 125 mph (205 km/h) near Buras-Triumph, Louisiana. At landfall, hurricane-force winds extended outward 120 miles (190 km) from the center and the storm's central pressure was 920 mbar. After moving over southeastern Louisiana and Breton Sound, it made its third landfall near the Louisiana/Mississippi border with 120 mph (195 km/h) sustained winds, still at Category 3 intensity

Figure 3: Hurricane Katrina at Landfall

On August 29, Katrina's storm surge caused several breaches in levees around New Orleans. Most of the city was subsequently flooded, as the breached drainage and navigation canals allowed water to flow from the lake into low areas of the city and Saint Bernard Parish. The storm surge also devastated the coasts of Mississippi and Alabama, making Katrina the most destructive and costliest natural disaster in the history of the United States, and the deadliest hurricane since the 1928 Okeechobee Hurricane. The total damage from Katrina is estimated at $81.2 billion (2005 U.S. dollars), nearly double the cost of the previously most expensive storm, Hurricane Andrew, when adjusted for inflation. 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. From this the NHC concluded that it is likely that much of the city experienced sustained winds of Category 1 or Category 2 strength.

Because of the large loss of life and property along the Gulf Coast, the name Katrina was officially retired on April 6, 2006 by the World Meteorological Organization at the request of the U.S. government. It was replaced by Katia on List III of the Atlantic hurricane naming lists, which will next be used in the 2011 Atlantic hurricane season.

My next post will be tomorrow and it will cover Hurricane Andrew (1992)