National Weather Service bulletin for Hurricane Katrina

Hurricane Katrina was the costliest natural disaster and one of the five deadliest hurricanes in the history of the United States.

paddleThe storm is currently ranked as the third most intense United States landfalling tropical cyclone, behind only the 1935 Labor Day hurricane and Hurricane Camille in 1969. Overall, at least 1,245 people died in the hurricane and subsequent floods, making it the deadliest United States hurricane since the 1928 Okeechobee hurricane. Total property damage was estimated at $108 billion (2005 USD), roughly four times the damage wrought by Hurricane Andrew in 1992 in the United States.

new-orleansThe eleventh named storm and fifth hurricane of the 2005 Atlantic hurricane season, Katrina originated over the Bahamas on August 23 from the interaction between a tropical wave and the remnants of Tropical Depression Ten. Early the following day, the new depression intensified into Tropical Storm Katrina. The cyclone headed generally westward toward Florida and strengthened into a hurricane only two hours before making landfall at Hallandale Beach and Aventura on August 25. After very briefly weakening to a tropical storm, Katrina emerged into the Gulf of Mexico on August 26 and began to rapidly deepen. The storm strengthened to a Category 5 hurricane over the warm waters of the Gulf of Mexico, but weakened before making its second landfall as a Category 3 hurricane on August 29 in southeast Louisiana.

The National Weather Service bulletin for the New Orleans region of 10:11 a.m., August 28, 2005 was a particularly sinister warning issued by the local Weather Forecast Office in Slidell, Louisiana, warning of the devastation that of Hurricane Katrina could wreak upon the Gulf Coast of the United States, and the torrent of pain, misery and suffering that would follow once the storm left the area.

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An NWS assessment of its Hurricane Katrina activity found that because of “the unprecedented detail and foreboding nature of the language used, the statement helped reinforce the actions of emergency management officials as they coordinated one of the largest evacuations in U.S. history.” The bulletin “helped reinforce the message from emergency management officials for residents in southeast Louisiana and southern Mississippi to heed evacuation orders from local officials.”

National Weather Service (NWS) provided accurate hurricane weather tracking forecasts with sufficient lead time.

On the evening of August 25, 2005, Hurricane Katrina made landfall as a Category 1 hurricane near the Miami-Dade–Broward county line in southern Florida and weakened into a tropical storm as a result. The next morning, after passing over the state, Tropical Storm Katrina moved into the Gulf of Mexico, and reintensified back to hurricane strength. As the hurricane passed over the warm waters of the Loop Current, the hurricane began to undergo rapid deepening.

At 11:00 p.m. EDT August 26, approximately 56 hours before Katrina’s landfall near Buras, Louisiana, the National Hurricane Center had predicted that the Greater New Orleans area could face a direct hit by the storm.  As New Orleans is located on the Mississippi River Delta and parts of the city are below sea level, a strong hurricane could have a devastating effect on the city. Previous warnings, such as the one made by the Houston Chronicle in 2001, told of a disaster that “would strand 250,000 people or more, and probably kill one of 10 left behind as the city drowned under 20 feet of water” following a severe hurricane making landfall on the city.

The National Hurricane Center’s director, Max Mayfield, indicated that the Mississippi/Louisiana area has “the greatest potential for nightmare scenarios,” and that this has been known for at least the three decades he has worked at the NHC. Other publications, such as Popular Mechanics, Scientific American, and The Times-Picayune gave doomsday scenarios in which a sinking city would drown and its residents would be left homeless.

sad-texas-familyIn 1965, Hurricane Betsy made landfall just south of New Orleans, causing widespread flooding in the city. As a result, a system of levees was authorized by Congress to handle future storm events. However, the protection given by this system was limited to hurricanes up to Category 3 intensity on the Saffir-Simpson Hurricane Scale.

Three days before Katrina’s second and third landfalls, the National Hurricane Center began predicting that the storm would make landfall as a major hurricane.  By the next morning, on August 27, the NHC issued a hurricane watch that included the New Orleans metro area,  which was upgraded to a hurricane warning by 10:00 p.m. CDT that same evening.  At this point, Katrina was a Category 3 hurricane with 115 mph (185 km/h) winds and about 335 miles (540 km) to the south-southeast of the Mississippi River’s mouth.