An Explanation of Hurricane Categories

Residents that live along the coastlines of the United States, and visitors to these locales, are well advised to educated themselves as to the dangers posed by the natural phenomenon known as “Hurricanes.” Hurricanes are tropical cyclones born over very warm ocean waters. They vary greatly in size, strength, and their potential for destruction to both property and lives.

Meteorologists have many tools at their disposal to help forecast and track developing hurricanes, but perhaps one of the most useful tools in their weather-related arsenal is one called “The Saffir-Simpson Hurricane Wind Scale.”

Developed by Herb Saffir, a wind engineer, and Bob Simpson, a meteorologist, the Saffir-Simpson Scale is used to inform the public about the potential for damages from hurricanes. It details the types of damages to expect and the overall scope of those damages, using five different category levels based on wind speed intensity. Earlier versions of The Saffir-Simpson Scale included data on storm surge and central storm pressure, in addition to wind speeds to classify a hurricane in one of five categories.  The revised Saffir-Simpson Wind Scale no longer includes this data, opting to rely on wind speeds alone to determine a hurricane’s potential impact on an area.

A Category One Hurricane is one that has sustained winds of 74-95 mph. A hurricane of this strength will produce some damage, especial from loose flying objects left unsecured outdoors. Mobile homes are particularly vulnerable to hurricanes of any strength, especially if they are not properly tied down. Broken windows, the loss of roof shingles, or, if not properly constructed, entire roofs, can be expected with a Category One hurricane. Downed tree limbs, power lines, and damaged signs, fences and overhead canopies can also be incurred during a storm of this strength. It should be noted that a hurricane that is expect to be stronger than a Category One, should prompt individuals in low-lying areas, and older, less secure housing, to evacuate their homes and seek shelter in a sturdy building.

A Category Two Hurricane is one that has sustained winds between 96 and 110 mph. A storm of this magnitude will cause extensive damage to property and a significant risk of injury or death to people and animals. Both older and newer mobile houses can be completely destroyed in a Category Two hurricane, and should be abandoned for safer shelter. There is a strong probability of homes sustained major roof damage or complete loss. Siding damage to homes and apartment buildings can be expected. Trees with shallow roots systems can be uprooted and felled. Wide-spread power loss can be expected. A storm of this strength can also be expected to effect water supplies, as power to local water systems fail.

A Category Three Hurricane is very powerful, with sustained wind speeds ranging from 111 to 130 mph. A storm in this category is extremely dangerous and damages are estimated to be devastating. A storm in this category can remove exterior walls and roofs of poorly constructed frame homes, causing total building collapse. Loss of water and electricity can last from several days to several weeks. Hurricane Ivan (2004) is a good example of a Category Three hurricane.

Category Four hurricanes are powerful storms with wind speeds between 131 to 155 mph. There is great risk for catastrophic damage with a Category Four hurricane, and they should never be taken lightly. Older mobile homes will be obliterated, and most new mobile homes will sustain near total destruction. With large amounts of debris flying through the air, broken windows and signage are almost guaranteed. The danger of life-threatening injuries to people, livestock, and pets is extremely high. With storms of this magnitude and size, power outages lasting from several weeks to possibly several months are common occurrences. There will be long term effects, such as lack of water, which can make the area unlivable for quite some time.

The last category on The Saffir-Simpson Scale is Category Five. Not many storms of this strength have hit The United States. These monsters are almost like mythical beasts. Unless someone personally witnessed and survived such a storm, it is very difficult to envision the utter destruction a Category Five hurricane can unleash on an area. Hurricane Andrew in 1992 was such a storm. For months after it made landfall, many said the Miami-Dade area looked as if either a bomb had gone off in it or they compared it to a war-zone. Category Five hurricanes produce complete structural collapse. There is an extremely high probability of devastating loss of life. Residential areas can expect to be cut off by loss of power, water, and other essentials supplies for weeks to possibly even months. The destruction posed by a Category Five Hurricane is complete.  Local civil governments will be completely overwhelmed by the destruction and loss of life.

By following The Saffir-Simpson Wind Scale guidelines for potential damages and danger to life, it is possible to take steps to help ensure individual safety and property. Thankfully, hurricanes, by the very nature of how they develop, usually allow for several days advance warning to secured property and allow for evacuation (if necessary), to help avoid un-needed risk of injury or possibly death.

As always, when a hurricane threatens to impact an area, it is always prudent to keep abreast of the storm’s development by monitoring local weather conditions and forecasts. Remember it is better to be smart than to be stubborn. If advised to evacuate a particular area for safer environs do the smart thing and heed the evacuation order. That decision could very well mean the difference in surviving a hurricane and being killed by one.

Sources

http://www.nhc.noaa.gov/pdf/sshws.pdf

http://www.nhc.noaa.gov/sshws.shtml

http://www.gohsep.la.gov/hurricanerelated/HURRICANECATEGORIES.htm