Hurricane Katrina

Hurricanes: An IntroductionA hurricane is a type of tropical cyclone, which is a generic term for a low pressure system that generally forms in the tropics. The cyclone is accompanied by thunderstorms and, in the Northern Hemisphere, a counter clockwise circulation of winds near the earth's surface. Tropical cyclones typically form over large bodies of relatively warm water. They derive their energy from the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation. This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled primarily by horizontal temperature contrasts. The strong rotating winds of a tropical cyclone are a result of the (partial)conservation of angular momentum imparted by the Earth's rotation as air flows inwards toward the axis of rotation. As a result, they rarely form within 5° of the equator. Tropical cyclones are typically between 100 and 4,000 km (62 and 2,485 mi) in diameter.

A cyclone is turned into a hurricane when the wind speed reaches 75 mph. In addition to strong winds and rain, tropical cyclones are capable of generating high waves, damaging storm surge, and tornadoes. They typically weaken rapidly over land where they are cut off from their primary energy source. For this reason, coastal regions are particularly vulnerable to damage from a tropical cyclone as compared to inland regions. Heavy rains, however, can cause significant flooding inland, and storm surges can produce extensive coastal flooding up to 40 kilometres (25 mi) from the coastline. Though their effects on human populations are often devastating, tropical cyclones can relieve drought conditions. They also carry heat energy away from the tropics and transport it toward temperate latitudes, which may play an important role in modulating regional and global climate.

Katrina: An InsightHurricane Katrina was the deadliest and most destructive Atlantic tropical cyclone of the 2005 Atlantic hurricane season. It was the costliest natural disaster, as well as one of the five deadliest hurricanes, in the history of the United States. Katrina was the sixth most intense Atlantic hurricane ever, part of the 2005 season that included three of the six most intense Atlantic hurricanes ever (along with #1 Wilma and #4 Rita). At least 1,833 people died in the hurricane and subsequent floods, making it the deadliest U.S. hurricane since the 1928 Okeechobee hurricane; total property damage was estimated at $81 billion (2005 USD), nearly triple the damage brought by Hurricane Andrew in 1992.

Katrina’s Origin and Landfall

Hurricane Katrina formed as Tropical Depression Twelve over the south eastern 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 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, growing from a Category 3 hurricane to a Category 5 hurricane in just nine hours. This rapid growth was due to the storm's movement over the "unusually warm" waters of the Loop Current, which increased wind speeds. On Saturday, August 27, the storm reached Category 3 intensity on the Saffire-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

1800 UTC that day, with maximum sustained winds of 175 mph (280 km/h) and a minimum central pressure of 902 mbar (26.6 inHg). The pressure measurement made Katrina the fourth most intense Atlantic hurricane on record at the time, only to be surpassed by Hurricanes Rita and Wilma later in the season; it was also the strongest hurricane ever recorded in the Gulf of Mexico at the time. However, this record was later broken by Hurricane Rita.[1]

Katrina made its second landfall at 1110 UTC (6:10 a.m. CDT) on Monday, 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 (27 inHg). 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. Katrina maintained strength well into Mississippi, finally losing hurricane strength more than 150 miles (240 km) inland near Meridian, Mississippi. It was downgraded to a tropical depression near Clarksville, Tennessee, but its remnants were last distinguishable in the eastern Great Lakes region on August 31, when it was absorbed by a frontal boundary. The resulting extratropical storm moved rapidly to the northeast and affected eastern Canada.

Preparedness for Hurricane Katrina

Hurricane Katrina was an extraordinary act of nature that spawned a human tragedy. It was the most destructive natural disaster in American history, laying waste to 90,000 square miles of land, an area the size of the United Kingdom. In Mississippi, the storm surge obliterated coastal communities and left thousands destitute. New Orleans was overwhelmed by flooding. All told, more than 1500 people died. Along the Gulf Coast, tens of thousands suffered without basic essentials for almost a week. But the suffering that continued in the days and weeks after the storm passed did not happen in a vacuum; instead, it continued longer than it should have because

of the failure of government at all levels to plan, prepare for and respond aggressively to the storm. These failures were not just conspicuous; they were pervasive. Among the many factors that contributed to these failures, there were four overarching ones:

1) long-term warnings went unheeded and government officials neglected their duties to prepare for a forewarned catastrophe

2) government officials took insufficient actions or made poor decisions in the days immediately before and after landfall

3) systems on which officials relied on to support their response efforts failed

4) government officials at all levels failed to provide effective leadership. These individual failures, moreover, occurred against a backdrop of failure, over time, to develop the capacity for a coordinated, national response to a truly catastrophic event, whether caused by nature or man-made.

The results were tragic loss of life and human suffering on a massive scale.

Hurricane Katrina : Date Timeline

Initial four days:

1. Tropical Depression Twelve2. Tropical Storm Katrina3. Category 1 hurricane4. Weakens to tropical storm5. Strengthens to Category 2 over Gulf of Mexico

27th August, Saturday1. Strengthens to Category 3, and doubles in size2. Louisiana implements Evacuation Plan3. Highway contra-flow on key routes4. Evacuation orders5. Shelters begin opening6. Activating disaster response teams7. Presidential emergency declarations