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Chapter 4

She Breathes

As the warm waters of the Gulf Stream move northward along the Mid-Atlantic, winding their way through the Caribbean, the warm weather of summer raises the temperatures of the surrounding waters. Prevailing seasonal weather patterns spurred on by the moisture of the warm waters create small tropical storm centers. Many of these small storms are brought into being, generate winds, rain, and frustrate tourists, only to fade away to brighter days, warm beaches, and pleasant weather.

Occasionally, some of these local tropical disturbances begin to nurse off of the warm waters, prevailing winds and weather. These are the children of hurricanes. They grow and pick up momentum. The warm temperatures of the Caribbean air and water become the devil’s milk for the child’s growth.

Hurricane season is considered the time beginning in mid-June and ending mid-September. During the season, the Northern Hemisphere experiences the summer months. Due the tilt of the Earth’s axis, the North Pole is a bit closer to the sun during this time of the Earth’s yearly cycle around the sun.

Extending from the equator northward, the waters of the Caribbean begin to warm. The currents of the Gulf Stream begin to speed up. The added warmth from the season begins to breathe energy into the waters. Global wind patterns over this area bring the colder prevailing winds streaming northward from the Antarctic.

The warming water and surface temperatures interact with the colder jet stream to create a cyclical interactive loop. The warm air rises and is cooled by the jet stream.

Ultimately, cyclic bands of pressure differences are generated.

So it goes with the changing of the seasons. The glory of Mother Nature proceeds as she endures her cycles. Sometimes she tends towards calm and at other times towards rage. Her cycles sometimes mixed with the tidal energies of the seas.

In the Northern Hemisphere, when conditions are right, a system of rotating energy can develop typified by low-pressure induced patterns rotating in a counter clockwise direction.

Interestingly, their equivalents in the Southern Hemisphere rotate clockwise. The rotational direction is said to be related to the weather momentum following the rotational axis of the Earth due to a tidal force called the Coriolis Effect.

Sometimes the energy cycles continue to be fed. As the pressure differences in the cycles increase, a tropical depression is formed. If she continues to be nursed, she grows requiring more warm water and moisture. She eventually enters adolescence as a tropical storm. She is a beauty now, and the eyes of the world fall upon her. Satellites track her movements, beaming images and snapshots of her majesty to the many global Hurricane Watch Centers. If the natural cycles are so inclined, she will grow into adulthood as a hurricane.

As she grows, she will continue her ravaging by sucking up the warmth of the water, taking the energy of warmer temperatures and translating that energy by growing in strength and ferocity. She will continue to grow until her food source is removed. If the waters she rages upon become regionally colder or shallower or if she stumbles off her water path and onto land, her energy will not be fed, and she will begin losing her strength and vitality. She will eventually fade away leaving only the path of where she had come behind her and possibly human memories of her existence, to be reborn with a new name and new temper as Mother Earth sees fit.

Hurricanes are classified by a rating system known as the Saffir-Simpson Scale, which is based upon the sustained wind speed generated by the storm. The Saffir-Simpson Hurricane Scale is a 1-5 rating based on the hurricane's wind intensity.

Category One Hurricane:

Wind speeds from 74 to 95 miles per hour. Storm surges are generally from 4 to 5 feet above normal. Typically, there is no real damage to building structures.

Category Two Hurricane:

Wind speeds from 96-110 miles per hour. Storm surges generally 6 to 8 feet above normal. Some roofing material, door, and window damage of buildings. Typically, there is damage to shrubbery and trees with some trees blown down and significant damage to mobile homes and piers.

Category Three Hurricane:

Wind speeds from 111-130 miles per hour. Storm surges are generally 9 to 12 feet above normal. Structural damage to small residences and buildings is typical.

Category Four Hurricane:

Wind speeds from 131-155 miles per hour. Storm surges generally 13 to 18 feet above normal. Complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage can occur to doors and windows. Low-lying escape routes may be cut by rising water 3 to 5 hours before arrival of the center of the hurricane.

Category Five Hurricane:

Wind speeds greater than 155 miles per hour. Storm surges generally greater than 18 feet above normal. Complete roof failure on many residences and industrial buildings. Complete building failures common with small utility buildings blown over or away. Complete destruction of mobile homes. Severe and extensive window, door, and roof damage occurring.

Note that in terms of damage, the increasing categories in terms of destructive potential do not follow a linear progression. In fact, with increases of wind velocity the damage potential increases exponentially, i.e. a Category 5 storm has 500 times the damage potential of a Category 1 storm.

Sustained wind speeds represent a mean speed of the winds as measured across a cross-section of the storm and are usually calculated from a one-minute average. Gusts can surge well above the reported sustained wind speeds. Furthermore, the sustained wind velocities are far higher in the center of the storm near the eye-wall. As her reach extends radially away from her eye, her wind speeds decrease and her momentum is reduced.

Since Bienville’s time to the present, New Orleans and the many inhabited areas to the south and along the Gulf Coast have been plagued by hurricanes and floods. Indeed, flooding and storms have literally shaped the historical, cultural, and geographical evolution of these areas.

The National Weather Service has reported a history of notable hurricanes extending as far back as 1856. In 1856, the Last Island Storm occurred. The storm was named for the Isle Derniere where 200 people perished. She was a Category 4 storm. New Orleans reportedly received 13 inches of rain during this storm.

Before the appearance of modern forecasting tools, large death tolls from hurricanes were more common. The Chenier Caminada storm of 1893, thought to be a Category 4, is estimated to have killed about 2,000 people. The hurricane's unofficial name comes from the island that lost 779 people to the storm. The hurricane produced a storm surge of at least 15 feet. By contrast, the deadliest hurricane in U.S. history was the Galveston, Texas, storm of 1900 that is believed to have killed over 8,000 people.

On September 20^th, 1909, a Category 4 hurricane stormed ashore at Grand Isle, Louisiana, and killed about 350 people. Heavy winds and a storm surge of 15 feet tossed boats out of the water and destroyed crops.

The Great Miami storm of 1926 was a Category 4 hurricane which cut a deadly path across the city of Miami on August 18^th, producing a storm surge of 15 feet. It then moved across the Gulf of Mexico to strike the Alabama-Florida border before reaching Louisiana. At least 243 people were dead when it was all over.

Hurricane Audrey of 1957 landed near the border of Louisiana and Texas on June 27^th. She killed at least 390 people. A storm surge of 12 feet was reported, with waves reaching 20 feet and higher. Wildlife were reported fleeing the area where Audrey hit the day before the storm arrived, including thousands of crawfish seen moving out of the marshes around Cameron, LA.

In 1965, Hurricane Betsy generated a storm surge of 10 feet which reached New Orleans when Betsy made landfall on September 9^th. The city suffered some of the worst flooding it had seen in decades. The storm surge on the coast was awe inspiring; Grand Isle experienced a 15.7 foot surge and wind gusts to 160 mph. The Orleans Levee Board required that levees be raised to 12 feet after assessing the storm's impact. Betsy resulted in 58 Louisiana deaths, and 81 overall.

In terms of deaths, damage and power, 1969’s Hurricane Camille ranks as one of the very worst storms to hit the coasts of Louisiana and Mississippi. A Category 5 storm, she killed 256 people with winds that topped 200 miles per hour and a storm surge that reached at least 20 feet when she landed on August 17^th. More than 5,000 homes were destroyed.

During Hurricane Andrew of 1992, 7 people died and 94 were injured. On August 26^th, Andrew’s winds were measured at up to 153 mph at New Iberia, Louisiana. A barge on Bayou Teche in St. Mary Parish recorded winds of 173 miles per hour. At his peak, Andrew was rated as a Category 5 storm. Overall, the storm killed 23 people in the United States.

In 2004, Hurricane Ivan, a Category 3 storm, made landfall at Gulf Shores, Alabama on September 16^th with winds of 130 miles per hour. Ivan was more remembered for the damage he did to the Caribbean, killing more than 30 people in Grenada and at least 20 in Jamaica. He took meteorologists by surprise by moving over the eastern U.S. and back out to sea to regain strength, returning to the Gulf of Mexico as a tropical storm. Ivan's second trip to the Gulf resulted in very little additional damage.

The Gulf Coast states have had their history integrated with the onslaught of hurricanes. A general loss of elevation of the area through erosion and depositional imbalances of the Mississippi River Delta system, the loss of the natural protective barrier of marshlands extending out into the Gulf, the general sinking of the area due to continental crustal subsidence, and the overall change in energy balance due to the warmer temperatures of the Caribbean waters all contribute to a higher frequency of severely damaging storms.

Record temperatures for the summer of 2005 kept the Gulf of Mexico unusually warm. The warm water is the primary energy giver to hurricanes, and as a result, the hurricane season of 2005 yielded 7 major hurricanes. The 5 that made landfall--Dennis, Emily, Katrina, Rita and Wilma--were responsible for over 100 billion dollars in damage and claimed an estimated 3865 deaths.

The 2005 season began on June 1^st, 2005 and lasted until November 30^th, although storm activity persisted until January of 2006. A record 28 tropical and subtropical storms formed, out of which the 7 major hurricanes formed. 5 of these major storms became Category 4 hurricanes and, Katrina and Wilma, became Category 5 storms.

Some have pointed to 2005 as an example of global warming. In the current lingo, the concept of global warming has morphed into the concept of climate change. Climate does change naturally, as is clearly evidenced in the geological record. Climate will always change. Likely, as our geological past indicates, it will increase in warmth for certain cycles and increase in cold for others as it has always done in the 4.6 billion years lifespan of our planet.

To say as a matter of fact that ‘global warming’ causes increased hurricane activity is problematic. The chaotic nature of weather and complex global cycles makes it impossible to prove an event like Katrina is due to global warming. One has to look at many events, their frequency of occurrences, and their intensities. Yet with all that, the number of variables that play into the making of a Hurricane are so numerous that making one simple correlation to call a hurricane a ‘global warming’ event is simplistic at best.

A host of atmospheric and global factors has to be just right for a hurricane to form. Specifically, the temperature difference between the air and the sea surface plays a significant role in hurricane development. It is true that measurements have indicated that sea surface temperatures have been observed to increase. However, the difference in temperature between the sea surface and the air temperature appears to be a larger driving force and doesn’t really follow the ‘global warming’ postulate as it relates to frequency of occurrence. There is some suggestion, however, that increasing sea surface temperatures can generate an increase in Hurricane intensity.

In the end, the temperatures of the Gulf Coast since Katrina have not really been observed to increase. The variability appears to be related to a mechanism far more elaborate than a simple ‘global warming’ hypothesis.

More time and energy needs to go into taking all the steps possible to mitigate the destructive effects of these storms and providing more efficient responses than worrying about if it is a ‘global warming’ phenomena.