Hurricane Katrina(2005)
The strongest tropical storms are called hurricanes, typhoons or tropical
cyclones. The different names all mean the same thing, but are used in
different parts of the world. If these huge storms start in the Atlantic off the
west coast of Africa, they are called hurricanes.
In an average year over a dozen hurricanes form over the Atlantic Ocean and
head westwards towards the Caribbean, the east coast of Central America
and the southern USA (Florida in particular). Hurricanes may last as long as a
month and although they travel very slowly - usually at about 24 km/h (15
mph) - wind speeds can reach over 120 km/h (75 mph).
How hurricanes form
Hurricanes need a lot of heat to form and a sea surface temperature of at
least 26°C, which is why they usually occur over tropical seas. They also need
to be between 5 and 20° north or south of the equator. It works like this:
1. When this warm and wet air rises, it condenses to form towering clouds,
heavy rainfall. It also creates a low pressure zone near the surface of the
water.
2. Rising warm air causes the pressure to decrease at higher altitudes. Warm
air is under a higher pressure than cold air, so moves towards the ‘space’
occupied by the colder, lower pressure, air. So the low pressure ‘sucks in’ air
from the warm surroundings, which then also rises. A continuous upflow of
warm and wet air continues to create clouds and rain.
3. Air that surrounds the low pressure zone at the centre flows in a spiral at
very high speeds - anti-clockwise in the northern hemisphere - at speeds of
around 120 km/h (75 mph).
4. Air is ejected at the top of the storm – which can be 15km high – and falls to
the outside of the storm, out and over the top, away from the eye of the
storm. As this happens, it reduces the mass of air over the ‘eye of the
storm’ - causing the wind speed to increase further. Some ejected air also
cools and dries, and sinks through the eye of the storm, adding to the low
pressure at the centre.
5. The faster the winds blow, the lower the air pressure in the centre, and so
the cycle continues. The hurricane grows stronger and stronger.
6. Seen from above, hurricanes are huge circular bodies of thick cloud around
450 km (300 miles) wide. The cloud brings heavy rain, thunder and
lightning.
7. In the centre is the eye of the hurricane, about 45 km across (30 miles)
across. Often there will be no clouds in the eye. Seen from below it will
seem calmer, with a circle of blue sky above. The eye is formed because this
is the only part of the hurricane where cold air is descending.
In the northern hemisphere, the prevailing easterly tropical winds tend to
steer hurricanes toward land - although their course is unpredictable. As
hurricanes move inshore, their power gradually reduces because their energy
comes from sucking up moist sea air.
(BBC Bitesize website, 2014)
HURRICANE KATRINA: BEFORE THE STORM
The day before Katrina hit, New Orleans Mayor Ray Nagin issued the city’s
first-ever mandatory evacuation order. He also declared that the Superdome,
a stadium located on relatively high ground near downtown, would serve as
a “shelter of last resort” for people who could not leave the city. (For
example, some 112,000 of New Orleans’ nearly 500,000 people did not have
access to a car.) By nightfall, almost 80 percent of the city’s population had
evacuated. Some 10,000 had sought shelter in the Superdome, while tens of
thousands of others chose to wait out the storm at home.
HURRICANE KATRINA: STORM AND FLOODING
By the time Hurricane Katrina struck New Orleans early in the morning on
Monday, August 29, it had already been raining heavily for hours. When the
storm surge (as high as 9 meters in some places) arrived, it overwhelmed
many of the city’s unstable levees and drainage canals. Water seeped
through the soil underneath some levees and swept others away altogether.
By 9 a.m., low-lying places like St. Bernard Parish and the Ninth Ward were
under so much water that people had to scramble to attics and rooftops for
safety. Eventually, nearly 80 percent of the city was under some quantity of
water.
Hurricane Katrina was the largest and 3rd strongest hurricane ever recorded
to make landfall in the U.S.In New Orleans, the levees were designed for
Category 3, but Katrina peaked at a Category 5 hurricane, with winds up to
175 mph. The storm surge from Katrina was 20-ft (six meters) high.705
people are reported as still missing as a result of Hurricane Katrina.
 Hurricane Katrina affected over 15 million people in different factors
such as economy, evacuations, gas prices or drinking water.The final
death toll was at 1,836, primarily from Louisiana (1,577) and
Mississippi (238).
 An estimated 80% of New Orleans was under water, up to 20 ft deep in
places. Hurricane Katrina caused $81 billion in property damages, but
it is estimated that the total economic impact in Louisiana and
Mississippi may exceed $150 billion, earning the title of costliest
hurricane ever in US history.
 Hurricane Katrina impacted about 90,000 square miles.The region
affected by the storm supported roughly 1 million non-farm jobs, and
still, hundreds of thousands of local residents were left unemployed by
the hurricane.
 More than 70 countries pledged monetary donations or other
assistance after the hurricane. Kuwait made the largest single pledge
of $500 million, but Qatar, India, China, Pakistan and Bangladesh made
very large donations as well.
National Geographic
HURRICANE KATRINA: THE AFTERMATH
Many people acted heroically in the aftermath of Hurricane Katrina. The
Coast Guard, for instance, rescued some 34,000 people in New Orleans
alone, and many ordinary citizens commandeered boats, offered food and
shelter, and did whatever else they could to help their neighbors. Yet the
government–particularly the federal government–seemed unprepared for
the disaster. The Federal Emergency Management Agency (FEMA) took days
to establish operations in New Orleans, and even then did not seem to have
a sound plan of action. Officials, even including President George W. Bush,
seemed unaware of just how bad things were in New Orleans and elsewhere:
how many people were stranded or missing; how many homes and
businesses had been damaged; how much food, water and aid was needed.
Katrina had left in her wake what one reporter called a “total disaster zone”
where people were “getting absolutely desperate.”
For one thing, many had nowhere to go. At the Superdome in New Orleans,
where supplies had been limited to begin with, officials accepted 15,000
more refugees from the storm on Monday before locking the doors. City
leaders had no real plan for anyone else. Tens of thousands of people
desperate for food, water and shelter broke into the Ernest N. Morial
Convention Center complex, but they found nothing there but chaos.
Meanwhile, it was nearly impossible to leave New Orleans: Poor people
especially, without cars or anyplace else to go, were stuck. For instance,
some people tried to walk over the Crescent City Connector bridge to the
nearby suburb of Gretna, but police officers with shotguns forced them to
turn back.)
Katrina pummeled huge parts of Louisiana, Mississippi and Alabama, but the
desperation was most concentrated in New Orleans. Before the storm, the
city’s population was mostly black (about 67 percent); moreover, nearly 30
percent of its people lived in poverty. Katrina worsened these conditions,
and left many of New Orleans’s poorest citizens even more vulnerable than
they had been before the storm.
In all, Hurricane Katrina killed nearly 2,000 people and affected some 90,000
square miles of the United States. Hundreds of thousands of evacuees
scattered far and wide. Today, after years of recovery and rebuilding efforts,
people along the Gulf Coast have made great strides in returning to life as
usual even as they continue to rebuild.
A+E Network Corp (2014), A&E
Television Networks,
Flooding caused by Hurricane Katrina in New Orleans 2005
There was much criticism of the authorities for their handling of the disaster.
Although many people were evacuated, it was a slow process and the
poorest and most vulnerable were left behind. $50 billion in aid was given by
the government.
The UK government sent food aid during the early stages of the recovery
process. The National Guard was mobilised to restore and maintain law and
order in what became a hostile and unsafe living environment.
Preparation and prediction
Preparation and prediction techniques
can be very different in MEDCs and LEDCs.
MEDCs have the resources and technology to predict and monitor the
occurrence of storms, eg using satellites and specially equipped aircraft. They
are also equipped to train the emergency services appropriately and to
educate people about necessary precautions.
Storm warnings can be issued to enable the population to evacuate or
prepare themselves for the storm. People can prepare by storing food and
water or boarding up their windows.
Storms bring destruction ashore in many different ways. When a hurricane
makes landfall it often produces a devastating storm surge that can reach 20
feet (6 meters) high and extend nearly 100 miles (161 kilometers). Ninety
percent of all hurricane deaths result from storm surges.
A hurricane’s high winds are also destructive and may spawn tornadoes.
Torrential rains cause further damage by spawning floods and landslides,
which may occur many miles inland.
The best defense against a hurricane is an accurate forecast that gives people
time to get out of its way. The National Hurricane Center issues hurricane
watches for storms that may endanger communities, and hurricane warnings
for storms that will make landfall within 24 hours.
National geographic (2013)
Prevention of potential damage
To prepare for a hurricane, you should take the following measures:
 Learn the elevation level of your property and whether the land is
flood-prone. This will help you know how your property will be
affected when storm surge or tidal flooding are forecasted.
 Identify levees and dams in your area and determine whether they
pose a hazard to you.
 Learn community hurricane evacuation routes and how to find higher
ground. Determine where you would go and how you would get there
if you needed to evacuate.
Make plans to secure your property:
 Cover all of your home’s windows.
Permanent storm shutters offer the best
protection for windows. A second option is to
board up windows with 5/8” exterior grade or marine plywood, cut to
fit and ready to install. Another year-round option would be
installation of laminated glass with impact-resistant glazing. Tape does
not prevent windows from breaking.
 Install straps or additional clips to securely fasten your roof to the
frame structure. This will reduce roof damage.
 Be sure trees and shrubs around your home are well trimmed so they
are more wind resistant.
 Clear loose and clogged rain gutters and downspouts.
 Reinforce your garage doors; if wind enters a garage it can cause
dangerous and expensive structural damage.
 Plan to bring in all outdoor furniture, decorations, garbage cans and
anything else that is not tied down.
FEMA Hurricane planning organization (2012)