From the first of June until the 30th of November of every year, people living along the Gulf of Mexico coast in the United States or Mexico, those living anywhere in the Caribbean or along the Atlantic Ocean, particularly the south eastern part of the United States along the Atlantic Ocean have to brace themselves for another hurricane season. The National Hurricane Center works closely with the National Oceanic and Atmospheric Administration to help make people aware of the risks posed by hurricanes when the warnings are issued.
Hurricanes are rated according to the Saffir-Simpson Hurricane Wind Scale. The scale, was initially created in 1969 by Dr. Herbert Saffir, a consulting engineer and Dr. Bob Simpson, who was the director of the National Hurricane Center. At the time, the world meteorological organization was preparing a report on the structural damage that wind storms could afflict on homes, and Dr. Simpson added additional information concerning the height of storm surges for each hurricane category to that report.
To better understand what the Saffir-Simpson scale really is, here is a look at what it was in the past, what it is designed to measure, how it works and what the hurricane categories mean.
*What is the Saffir-Simpson Hurricane Wind Scale?
The Saffir-Simpson wind scale puts hurricanes into five categories based on the intensity of wind speed, but only at the time of observation. This scale is designed to provide examples of the type of damage as well as the impact of winds at various intensities. For every category increase, the damage will generally rise by a factor of four.
The determining factor in the current scale is the maximum sustained surface wind speed. The way by which these things are determined is by recording the peak wind speed for one minute at the standard meteorological observation height of 33 feet over an exposure that is unobstructed. In hilly or mountainous areas, sustained wind speeds can be even stronger.
*Earlier versions of the scale –
Before the scale was changed so that the categories were determined almost solely by sustained wind speeds, the scale was known more simply as the Saffir-Simpson Hurricane Scale. This earlier scale confined its considerations to the central pressure and storm surge, and those were the only components that were used for determining the categories.
During the 1970’s and 1980’s, central pressure served as a proxy for wind speed intensity measures. Ever since sometime around 1990, it has been possible to calculate those wind speeds with far greater accuracy due to the availability of specially outfitted reconnaissance airplanes. These planes are able to record wind speeds from high in the sky through the use of very sophisticated and accurate scientific devices.
*The current scale –
The current scale determines the categories by measuring nothing but the peak wind speeds. Although other factors such as storm surge ranges and central pressure statements and the impact of floods are no longer considered, they are still important in the ultimate determination of the kind of damage that a hurricane can cause. The wind speed of Hurricane Katrina put it at a Category Three, but the damage caused by flooding and other things made this hurricane one of, if not THE costliest natural disaster in American history.
♥HURRICANE CATEGORIES♥ –
*Category One (Damage is considered minimal) –
A category one hurricane must have sustained winds that range between 74 and 95 mph. Hurricane Dolly that struck South Padre Island, Texas in 2008 was a Category One hurricane. Although damage will be minimal, unprotected windows may be broken, siding may be torn off of homes and there may also be short term power outages.
*Category Two (Damage is considered moderate) –
A category two hurricane will have sustained winds of 96-110 mph. Hurricane Frances made landfall at Port St. Lucie, Florida in 2004 as a category two storm. Older mobile homes will be heavily damaged, if not destroyed. Power outages and down trees will be commonplace, and moderate flooding may occur.
*Category Three (Damage is considered extensive)-
Category three hurricanes have sustained winds of between 111 and 130 mph. In 2004, Hurricane Ivan made landfall in Gulf Shores, Alabama. A category three hurricane can cause devastating damage. Mobile homes can be destroyed, other homes may incur roof damage or walls may collapse. Power outages will be commonplace as will flooding of low lying areas. Evacuation orders will likely be issued.
*Category Four (Damage is considered extreme) –
A category four hurricane will have sustained winds of 131 to 155 mph and the potential to cause catastrophic damage. Hurricane Charley made landfall at Punta Gorda, Florida. A category four hurricane will cause even more devastating damage, uprooting trees, toppling power lines, tearing apart buildings, signs, canopies, fences and more. Long term power outages can be expected and water shortages will make the area uninhabitable. Areas affected by downed power lines will become isolated. Mandatory evacuation orders may be issued.
*Category Five (Damage is considered catastrophic) –
A category five hurricane will have sustained winds of more than 155 mph. In 1992, Hurricane Andrew affected Coastal Ridge, Florida with category five strength winds. Elsewhere, areas of south Miami-Dade County experienced category four conditions.
The damage of a category five hurricane is almost unimaginable. It will be far more extreme than any of the other categories, and lives will be in danger. Flooding of low lying areas will be commonplace, and the storm surges may cause additional flooding. Tornadoes can be spawned off of a category five hurricane, and trees will be uprooted, any type of vegetation will be completely destroyed and power lines will fall. Mandatory evacuation orders will be issued. All basic necessities such as food, water and power will be unavailable, making areas affected by a category five hurricane completely uninhabitable for a lengthy period of time.
By understanding the Saffir-Simpson scale and how it works, we can better understand what to expect when we enter hurricane season. Knowing the type of damage that each of the categories will inflict can be helpful to people who need to have a survival plan and who need to know how to protect their homes. The more people know, the better able they will be to take the necessary measures to be prepared from the moment that hurricane season begins. For those who heed the warnings and take the time to be prepared, surviving a hurricane may be a major inconvenience, but it is something that can be endured. These preparations can be the very thing that ensures survival, no matter how minimal or massive the hurricane may be.
SOURCES:
Saffir-Simpson Hurricane Scale –
Hurricane Watch Net- Saffir Simpson Scale –
NHC & NOAA – The Saffir-Simpson Hurricane Wind Scale –
NHC – Saffir-Simpson Hurricane Wind Scale Summary Table –
