WX 101: Saffir-Simpson Scale

Weather 101: All
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The Saffir-Simpson Hurricane Wind Scale has become vital tool for alerting the public on the possible impacts of a hurricane.  The scale was designed by a wind engineer (Herb Saffir) and a meteorologist (Bob Simpson) to categorize hurricanes.  The scale does not address the potential for hurricane-related impacts, such as storm surge, floods, and tornadoes. 

Here are the categories:

Category 1 Hurricane (Winds of 74-95 mph)
A category 1 hurricane is considered to have very dangerous wind and some damage can be expected.  Older (before 1994) mobile homes could be destroyed, especially those not anchored properly.  Vinyl siding, carports and sun-rooms are a all vulnerable.  Even poorly constructed frame homes can experience major damage.  Unprotected windows can be broken by flying debris.  Even brick homes could take damage as masonry chimneys could be toppled.  Commercial signage, fences, and canopies all could suffer damage. 

A good example of a category one hurricane is Hurricane Dolly.

Category 2 Hurricane (Winds of 96-110 mph)
A category 2 hurricane will bring extremely dangerous winds and will produce extensive damage.  At this point there is substantial risk of injury or death to people, livestock, and pets due to flying and falling debris.  There is a very high chance that older (before 1994) mobile homes will be destroyed.  Roofs will likely be removed on poorly constructed frame homes.  Even well-constructed frame homes could see some major roofing and siding damage.  Unreinforced masonry walls can collapse.  Windows in high-rise building can be broken by flying debris and after the storm falling glass will pose a major threat.  Shallowly rooted trees will be snapped of uprooted.  In the area that see category 2 winds, complete power outages can be expected. 

Hurricane Frances is a good example of a category two storm. 

Category 3 Hurricane (Winds of 111-130 mph)
Devastating damage is expected to occur with a category three storm.  Nearly all older (pre 1994) mobile homes will be destroyed.  Most new mobile homes will have severe damage with the potential for complete roof failure and wall collapse.  Poorly constructed frame homes can be destroyed and the roof and exterior walls may all be removed.  Unprotected windows can be expected to be broken.  Many apartment and industrial buildings will have their roof covering damaged.  Most commercial signage, fences, and canopies will be destroyed.  Electricity and water may be unavailable for several days to a few weeks. 

Hurricane Ivan is a good example of a category three storm. 

Category 4 Hurricane (Winds of 131-155 mph)
Catastrophic damage is expected to occur with a category four storm.  Nearly all older (pre 1994) mobile homes will be destroyed and most newer mobile homes will be destroyed.  Poorly constructed homes could completely collapse and lose the roof.  Well-built homes also will have severe damage with extensive damage to roof covering, windows, and doors.  There will be large amounts of debris in the air, which will cause more damage.  The top floors of apartment buildings will have severe structural damage.  High-rise buildings will have most of the upper windows blown out.  Most trees will be snapped or uprooted and power poles will be downed.  Fallen tees and power poles will block roads and isolate many residential areas.  Power outages could last months.  Some areas will be uninhabitable for weeks or even months.

Hurricane Charley is an example of a Category 4 storm. 

Category 5 Hurricane (Winds of 155 mph or greater)
There is a very high risk for death of people, livestock, and pets even if indoors.  All mobile homes are likely to be destroyed and a high percentage of frame homes will be destroyed with total roof failure and wall collapse.  Large amounts of wind borne debris will be flying through the air.  Nearly all unprotected windows will suffer damage.  Unreinforced masonry walls will fail leading to the collapse of buildings.  Low-rise apartment buildings will be destroyed.  All windows of high-rises will be blown out.  All trees will likely be toppled or snapped. Power outages could last months and water shortages could be widespread. 

Hurricane Andrew is an example of a Category 5 storm. 

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