What is the Saffir-Simpson scale?

In 1972, American scientists Herbert Saffir and Robert Simpson developed the Saffir-Simpson Scale to classify the severity of hurricanes. This scale ranks hurricanes by the intensity of wind speeds. Hurricanes are divided into five categories, as described in the table below:


The Saffir-Simpson Scale
Category Sustained Winds Types of Damage Due to Hurricane Winds
1 74-95 mph
64-82 knots
119-153 km/h
Very dangerous winds will produce some damage: Damage to unanchored mobile homes; shrubs/small trees uprooted.

Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
2 96-110 mph
83-95 knots
154-177 km/h
Extremely dangerous winds will cause extensive damage: Some coastal flooding; damage to vegetation.

Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.
3
(major)
111-129 mph
96-112 knots
178-208 km/h
Devastating damage will occur: Inland flooding; trucks/cars swept away; trees uprooted; damage to small boats/structures; damage to all structures by floating debris.

Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
4
(major)
130-156 mph
113-136 knots
209-251 km/h
Extreme damage will occur: Roads/bridges washed away; major erosion of beaches.

Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
5
(major)
157 mph or higher
137 knots or higher
252 km/h or higher
Catastrophic damage will occur: Extensive flooding.

A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.

Contributing Source: NOAA

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