Topics Covered
Introduction – What is a Hurricane?
The Saffir-Simpson Hurricane Wind Scale
Hurricane Naming Convention
Potential Issues / Hazards of Hurricane
How to Protect your Home from a Hurricane
The Roof System
Exterior Openings
Fences and Porches
Sources
Introduction – What is a Hurricane?
A Hurricane is a violent tropical cyclone with winds moving around a low-pressure area at speeds of about 74 miles per hour. It is usually formed in the eastern Pacific Ocean, Gulf of Mexico, Caribbean Sea and southern Atlantic Ocean together with thunderstorms. The hurricane season lasts for several months during June to November in various parts. The Atlantic hurricane season begins in June and gets severe between mid-August to October, and the eastern Pacific hurricane season starts from May 15 and lasts till the end of November.
The storm surge resulting from a hurricane is a great life threat. Water levels can reach heights of over 20 feet at the coast and flash floods may also occur when hurricane strikes. Hurricanes can trigger mircrobursts, tornadoes and winds blowing at a speed of more than 155 miles per hour. Hurricanes that move slowly towards the mountain regions cause heavy rain, which would in turn produce mud slides or land slides.
The Saffir-Simpson Hurricane Wind Scale
The Saffir/Simpson scale is employed for rating the intensity of hurricanes and providing wind impact related information. This scale divides hurricanes into five categories on the basis of speed of the wind at a preset time.
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Category 1 - 74-95 mph
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Category 2 - 96-110 mph
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Category 3 - 111-130 mph
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Category 4 - 131-155 mph
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Category 5 – more than 155 mph
Hurricanes of category one and two are moderate and that of category five are strong. This scale is used for assessing the damage to property due to floods and hurricanes.
Hurricane Naming Convention
For several years, hurricanes were not named formally. Only the most devastating hurricanes were named after the name of places where they created severe damages. Later, different countries used different methods for naming hurricanes. For instance, several hurricanes in West Indies have derived their name from the particular saint’s day they had occurred. During World War 2, meteorologists in US started naming tropical cyclones in Pacific and Atlantic Oceans using women’s names.
Today, the names of the storms and hurricanes are selected by the World Meteorological Organization. The first tropical storm of the year is given a name starting with the letter A, the second storm is given a name starting with the letter B and so on. However, the letters Q, U, X, Y, and Z are not used as there are very few names starting with these letters and both male and female names are used. Eastern Pacific and Atlantic tropical storms will have different name lists. Some names of destructive storms such as Irene, Keith, Paloma, etc. are now retired.
Potential Issues / Hazards of Hurricane
The following section discusses some of the hurricane hazards:
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Strong winds - High winds of speeds of more than 74 mph are capable of destroying mobile homes and buildings and removing the roofing materials off the buildings.
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Storm Surge – It is the rise in water level as the swirling wind pushes the water towards the shore. The surge in turn develops the storm tide that increases the mean level of water affecting the roads, houses and other infrastructure. Reports state that several coastal communities have been destroyed by major storms like Hugo, Camille and Katrina.
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Rainfall and Flooding – Flooding caused by heavy rains is the most dangerous consequence of tropical cyclones. Nearly 81% of deaths occurred globally during 1970 to 1988 were due to drowning in floods, according to the reports of the National Hurricane Center.
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Tornadoes - Hurricanes are accompanied by tornadoes most of the times. Tornadoes are usually present in the hurricane center at which the thunderstorms take place. They consist of winds that circulate and move forward at a Fujita speed of F1 and F2.
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Beach Erosion - Loss in the width of beach may occur due to erosion resulting from strong winds.
How to Protect your Home from a Hurricane
The following techniques can be applied in houses to protect them from devastating rain and winds due to hurricanes:
The Roof System
Hurricane clips or straps can be fixed to the roof at a point where the roof truss is connected with the exterior wall. It is necessary to check whether the clips or straps are fastened tightly to avoid weakening of roofs. With gable-end roofs, the ends of the roofs are required to be braced. Further, in order to strengthen the gable ends, the steel angles need to be fixed to the gable.
Exterior Openings
Sliding doors, windows and French doors can be safeguarded using impact-resistant glazing or hurricane shutters. Some of the types of hurricane shutters include:
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Shade shutters
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Hurricane netting and fabric panels
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Accordion shutters
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Bahama shutters
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Rolldown shutters
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Colonial shutters
Shuttering can be performed using metal storm panels or plywood of 5/8 inch. It is important to secure the pins at the top and bottom of the double-entry doors.
Fences and Porches
During fencing, proper spacing needs to be allowed at the bottom of the ground for air to enter underneath the fence. Moreover, it is better to ensure that the porch roof is properly fixed to the exterior wall of the building.
Sources
http://www.reidsteel.com/information/hurricane_resistant_building.htm
http://www.inthpa.com/Whattodo.asp
http://www.fhba.com/index.cfm?referer=content.listAreaSummary&id=95
http://www.hurricaneproof.com/shutters.php
http://www.ready.gov/hurricanes