-Hurricane Katrina-The United States’ worst natural disaster to date has created situations and scenes similar to those seen in the aftermath of the Asian Tsunami last

December. Hurricane Katrina has left a legacy of ruin behind, and the world’s only superpower is

struggling to cope.

How powerful was the hurricane? How did it form? What did it do? What was the response?

Hurricane Katrina passing Florida on the far right. What is a hurricane?-A hurricane is a type of tropical cyclone-

Structurally, a tropical cyclone is a large, rotating system of clouds, wind and thunderstorm activity. The primary energy source of a tropical cyclone is the release of the heat of condensation from water vapor condensing at high altitudes. Because of this, a tropical cyclone can be thought of as a giant vertical heat engine.

The ingredients for a tropical cyclone include a pre-existing weather disturbance, warm tropical oceans, moisture, and relatively light winds aloft. If the right conditions persist long enough, they can combine to produce the violent winds, incredible waves, torrential rains, and floods associated with this phenomenon.

In order to continue to drive its heat engine, a tropical cyclone must remain over warm water, which provides the atmospheric moisture needed. The evaporation of this moisture is driven by the high winds and reduced atmospheric pressure present in the storm, resulting in a sustaining cycle. As a result, when a tropical cyclone passes over land, its strength will diminish rapidly.

How do Tropical Storms form?-A hurricane is a type of tropical cyclone-

Five factors are necessary to make tropical cyclone formation possible:

1. Sea surface temperatures above 26.5 degrees Celsius to at least a depth of 50 meters. Warm waters are the energy source for tropical cyclones. When these storms move over land or cooler areas of water they weaken rapidly.

2. Upper level conditions must be conducive to thunderstorm formation. Temperatures in the atmosphere must decrease quickly with height, and the mid-troposphere (the lowermost section of Earth’s atmosphere) must be relatively moist.

3. A pre-existing weather disturbance. This is most frequently provided by tropical waves—non-rotating areas of thunderstorms that move through the world's tropical oceans.

4. A distance of approximately 10 degrees or more from the equator, so that the Coriolis Effect is strong enough to initiate the cyclone's rotation.

5. Lack of vertical wind shear (change in wind velocity over height). High levels of wind shear can break apart the vertical structure of a tropical cyclone.

The thermal image here shows that the hurricane is relatively warm with the exception of its eye (the central point of circulation). This well contains sinking air, and although the weather inside the eye is calm, the sinking air reduces temperatures considerably.

-Timeline-August 23, 2005 - The U.S. National Hurricane Centre (NHC) issues a statement saying that Tropical Depression Twelve

had formed over the southeastern Bahamas.

August 24 morning - The storm system is upgraded to Tropical Storm Katrina.

August 25 - The storm is upgraded to become the fourth hurricane of the 2005 season.

First landfall

August 25

6:30PM - Katrina makes its first landfall in Florida as a Category 1 hurricane. At least 11 deaths in Florida are attributed to the storm.

August 26

A State of Emergency is declared for the state of Louisiana

August 27

Katrina is upgraded to a Category 3 hurricane.

New Orleans Mayor Ray Nagin calls for a voluntary evacuation of the city. The emergency plans rely on citizens to bring their own 3-day supply of food and water to the Superdome and Convention Center. Current Louisiana Emergency Evacuation guidelines allow use of public school buses. It is currently disputed whether or not they were used to transport the poor to the superdome.

National Hurricane Director Max Mayfield and President Bush call on Mayor Nagin to declare a mandatory evacuation.

August 28

12:40AM CDT - Katrina becomes a Category 4 hurricane.

7AM CDT - NWS/NOAA announces Katrina is a Category 5 hurricane.

10AM CDT – National Weather Service issues a bulletin predicting "devastating" damage.

10AM CDT - Mandatory evacuation is ordered for New Orleans City by Mayor Nagin and Governor Blanco after having been requested the previous day by National Hurricane Director Max Mayfield and President George Bush. However, neither of these sources are primary and other sources for this information seem to be missing. No public transportation is afforded the mostly poor citizens contrary to what the disaster plans called for. However, Nagin urged those people to seek rides with friends, family, neighbors and church members. Those who could not find rides were urged to get to the Superdome as quickly as possible. New Orleans Regional Transit Authority buses were scheduled to ferry people to the dome from 12 locations around the city, although these are quickly overwhelmed.

1PM CDT - Katrina becomes a Category 5 hurricane with maximum sustained wind speeds of 175 mph and gusts up to 215 mph. What normally takes 2 hours to drive to central Louisiana, becomes a 10 hour crawl.

August 298AM CDT - New Orleans: Rising water on both sides of the Industrial Canal9AM CDT - New Orleans: 6-8 feet of water in the Lower Ninth Ward. 11AM CDT - New Orleans: 10 feet of water in St. Bernard. 2PM CDT - New Orleans officials publicly confirm 17th Street Canal breach.August 301:30AM CDT - CNN reports that a levee on the 17th Street Canal, which connects into Lake Pontchartrain, suffered a two

city-block wide breach. It is later reported that a total of three levees are breached. Noon CDT - Homeland Security Secretary Michael Chertoff becomes aware that the New Orleans levee breaches cannot be

plugged. 10PM CDT - New Orleans Mayor Ray Nagin announces that the planned sandbagging of the 17th Street levee breach has

failed. 80 percent of New Orleans is underwater. Many instances of looting, including looting by police officers, reported in the city of New Orleans.The U.S. military moves additional ships and helicopters to the region. Hurricane Katrina gets downgraded to a tropical

depression. August 3110:00AM Governor Blanco finally makes the request for President Bush to send Federal troops to help with evacuations and

rescues. Air Force One views the devastation from the air.Governor Kathleen Blanco of Louisiana orders that all of New Orleans, including the Superdome, be evacuated. First report of relief supplies delivered to Superdome. New Orleans's 1,500 member police force is ordered to abandon search and rescue missions and turn their attention toward

controlling the widespread looting and a curfew is placed in effect. Mayor Ray Nagin calls for increased federal assistance.

The National Guard remain under their respective governors' control, which enables them to provide law-enforcement support in the affected regions.

State workers begin work at closing 17th Street Canal breach, U.S. Army Corps of Engineers adds resources to the task. 11PM EDT - U.S. government weather officials announce that the center of the remnant low of what was Katrina has been

completely absorbed by a frontal boundary in southeastern Canada, with no discernible circulation. The remnants of the hurricane cause roads in northern Quebec to be sectioned by heavy rainfall, isolating the north shore communities for several days.

-Facts and Figures-Duration

Aug. 23 - 31, 2005Highest winds

175 mph (280 km/h) sustainedDamages-Total

Damages estimated as high as $200 billion (Costliest Atlantic hurricane of all time)

Fatalities854, still rising.

Immediate and Short-Term Effects80% of New Orleans submerged; death toll could reach

100,000; Category 5 winds destroyed smaller buildings, heavily damaged larger buildings; Infrastructure mostly

damaged or submerged, Transport Links inoperable; burst levees are causing the spread of toxic depositions and

chemicals suspended in the floodwaters, polluting lakes and endangering lives.

Areas affectedBahamas, South Florida, Louisiana (especially Greater New

Orleans), Mississippi, Alabama, Florida Panhandle-Part of the 2005 Atlantic Hurricane Season-

Global Warming linked to increasing number of extreme tropical storms: warmer waters “fuel” the larger

hurricanes

-Anarchy in the Aftermath--Looting and Crime-Shortly after the hurricane ended on August 30th, some

residents of New Orleans who remained in the city began looting stores. Drug, convenience, clothing, and jewelry stores in the French Quarter and on Canal Street were hardest hit. "The looting is out of control. The French Quarter has been attacked," Councilwoman Jackie Clarkson said. "We're using exhausted, scarce police to control looting when they should be used for search and rescue while we still have people on rooftops."

By September 1st, conditions worsened. A national guardsman was wounded by a shooting outside the Superdome. Reports of carjacking, thefts, and rapes flooded the news. Nearly 5,000 National Guard troops were mobilized in Louisiana. "These troops know how to shoot and kill and I expect they will," Kathleen Blanco said.

Congressman Jefferson told ABC News, "There was shooting going on. There was sniping going on. Over the first week of September, law and order was gradually restored to the city. " A number of arrests were made near the New Orleans Convention Center.

The citywide anarchy disrupted relief efforts, and many of the dead were left lying in the streets, not dissimilar from the streets in Sumatra after the Asian Tsunami last year. Many civilians were encouraged to possess a firearm or weapon to defend themselves with until order was restored.

The national response to the natural disaster was considered to be inadequate: the evacuation plans were inappropriate for this kind of disaster, and were issued much later than they should have been; the effects of a hurricane on New Orleans were known, yet nothing was done to prepare for such an event, including reinforcing the levees.

-Health concerns-Aside from the lack of water, food, shelter and

sanitation facilities, there is growing concern that the prolonged flooding will lead to an outbreak of health problems for those who remain in the hurricane-affected areas. In addition to dehydration and food poisoning, there is also a potential for communicable disease outbreaks of diarrhea and respiratory illness, all related to the growing contamination of food and drinking water supplies in the area. In all likelihood, the death toll will rise as current conditions in the area persist.

Before the hurricane, government health officials prepared to respond, and the Centres for Disease Control and Prevention (CDC) began sending medical emergency supplies to locations near the worst-hit area within 48 hours after landfall.

There is concern the chemical plants and refineries in the area could have released their contents into the floodwaters. People who suffer from allergies or lung disorders, such as asthma, will have health complications due to toxic mold and airborne irritants. On Septmber 6th it was reported that Escherichia coli (E. coli) had been detected at unsafe levels in the waters that flooded New Orleans. The CDC reported on September 7th that five people had died of bacterial infection from drinking water contaminated with Vibrio Vulnificus, a bacterium from the Gulf of Mexico. Wide outbreaks of severe infectious diseases such as cholera and dysentery are not considered likely because such illnesses are not endemic in the United States.

-Response: National and International-Response Procedures

-Clockwise from top right-Helicopters drop sandbags into the flooded areas in an

attempt to stop the floodwater reaching other areas of New Orleans.

Floodwater is being pumped out of the city, beginning the long draining process.

Emergency workers begin the task of locating and identifying the dead under the ruins and waters.

Military convoys transport much-needed supplies into the city. These supplies, including medical and food supplies, have come from other countries other than the U.S., such as Russia, Canada and China.

A man lays dead on the roof of a car, too late to be rescued by the sparse and scattered emergency services.

The National Guard breach doorways to enforce the mandatory evacuation, which many believe was issued far too late.

With such a large area of devastation to cover, and with 80% of New Orleans still submerged, it is probable that it will take more than a year for the city to return to some sort of normality, with infrastructure repaired and transport links usable once again.