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Ch1: An Introduction to Gulf Coast Severe Storms and Hurricanes
- Texas A&M University Press
- Chapter
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Introduction As populations move toward coastal regions in ever increasing numbers, the impacts and associated costs of severe storms on coastal counties increase exponentially. A severe storm is usually considered to be a tropical storm or hurricane, but may also be a severely damaging hail storm, tornado or thunderstorm (doswell 1978). Each summer, a number of these storms enter the Gulf of Mexico and gain intensity as they hover over its warm waters (fig. 1.1). these storms have the potential to claim hundreds of lives and inflict tens of billions of dollars in damages. the recovery times in impacted areas vary significantly depending on the severity and location of the storm. in some cases, several years are required for infrastructure to fully recover from a severe storm or hurricane. in 2008, 87 million people were living in US coastal counties, an 84 percent increase from 1960. the Gulf Coast region stretches from the southern tip of Florida to the southern tip of texas, encompassing 56 counties and more than 5.8 million housing units (Wilson 2010). the region is home to over 15 million inhabitants and is among the most vulnerable areas to severe storms and hurricanes in the United States. in addition, the two largest petrochemical facilities in the world, the two largest refining areas in the United States, and over 4000 oil rig structures are located in this region . in order to fully comprehend and accurately analyze the risks presently faced by the Gulf Coast, an understanding of the mechanics and history of severe storms in the region is necessary , and is covered in detail in this introduction. An introduction to Gulf Coast Severe Storms and hurricanes Philip B. Bedient and Antonia Sebastian 1 Figure 1.1. Measuring over 445 miles across, hurricane Rita heads towards the texas/louisiana border. Rita caused a mass evacuation in texas and over 2.5 million people left houston in a matter of 24 hours. Photo courtesy nASA. [44.214.106.184] Project MUSE (2024-03-29 12:49 GMT) bedient and sebastian 3 Tropical Cyclone Development north Atlantic tropical cyclones form off the coast of West Africa, over the tropical oceans between 5 and 20 degreesnorthorsouthlatitude ,andinthe Gulf of Mexico. traveling westward, tropical cyclones may make landfall along the coast of the eastern United States, Caribbean, and Central America (fig. 1.2). those that make landfall in the Caribbean or over southern Florida often have enough strength to cross land and enter the Gulf of Mexico . despite being severely weakened, these storms can strengthen across the Gulf of Mexico. the warm waters, high humidity, and low wind shear present in the Gulf during summer allow hurricanes to rebuild and gain strength, leaving coastal counties at a great risk for hurricane landfall. With extreme amounts of rainfall and winds that can exceed 186 mph, these storms are among the most destructiveonearth (Bedientetal.2008). Figure 1.2. Atlantic Basin tropical cyclone activity 1851–2005. tropical cyclones that became major hurricanes are colored in yellow. Photo courtesy nOAA. gulf coast severe storms and hurricanes 4 Severe tropical cyclones have different names depending upon their location (i.e. typhoon, cyclone, baguio); the north American term, used in this discussion, is hurricane. hurricanes require water temperatures of greater than 80 degrees Fahrenheit at depths up to 50 meters below the surface and warm and moisture-laden air, which possesses an enormous capacity for heat energy. Under these conditions, the condensation from vapor to water sustains hurricane development. An in-depth discussion of the components and mechanics of hurricane formation can be found in Chapter 3. Tropical Storms Each year, tropical storms (wind speeds 39–73 mph) wreak major damage on coastal communities. Slower wind speeds reduce the risk of damage caused by storm surge and tornados , but increase the risk of flooding because these storms typically have slower forward movement. the most famous tropical storm to make landfall on the Gulf Coast was tropical Storm Allison. Allison made landfall on the afternoon of June 5, 2001 in Freeport, texas. the storm quickly weakened into a tropical depression, but continued circulating over the houston/Galveston Area for four days, dumping incredible amounts of rainfall on downtown houston and the texas Medical Center. Much of the area received more than 24 inches of rain in nine hours and flooding from the storm caused 41 deaths and more than $5 billion in damages. in parts of downtown houston and at the texas Medical Center, three major facilities sustained...