About The Saffir-Simpson Scale
April 24, 2008
By WeatherBug Meteorologist, Mike Hollen
放大Similar to how the Fujita scale categorizes tornadoes; the Saffir-Simpson Scale categorizes hurricanes by current winds and even the expected storm surge.
It was developed in the late 1960s by Herbert Saffir to help the public gauge the expected damage from any hurricane at landfall. In the early 1970s, Robert Simpson, then the National Hurricane Center`s director, added to and refined the scale that Saffir created a few years earlier.
Storm surge is technically part of the scale, but since the exact height of the surge is difficult to predict, the peak sustained one-minute winds in a hurricane are the determining factor, while the storm surge is more of a guideline.
Category One
Winds 74-95 mph (64-82 kt or 119-153 km/hr). The storm surge is about 4-5 feet above normal. Most damage is limited to unanchored objects (mobile homes, traffic lights, signs, etc.), trees and bushes. Coastal flooding is minimal with some minor pier damage.
Category Two
Winds 96-110 mph (83-95 kt or 154-177 km/hr). The storm surge is about 6-8 feet above normal. Flooding begins 2-4 hours before the hurricane`s landfall with moderate pier damage. Large trees are blown over. There is significant damage to unanchored buildings, while small boats may break free.
Category Three
Winds 111-130 mph (96-113 kt or 178-209 km/hr). Storm surge is 9-12 feet above normal. Mobile homes and other unanchored buildings are destroyed. Small structures sustain moderate damage. Large trees and bushes are blown over. Significant coastal flooding occurs 3-5 hours before landfall. Small buildings are destroyed by flooding and larger buildings are damaged from floating debris. Residents within a few blocks of the coastline should evacuate.
Category Four
Winds 131-155 mph (114-135 kt or 210-249 km/hr). Storm surge is 13-18 feet above normal. Small structures sustain major damage, while larger structures sustain moderate damage. Mobile homes are completely destroyed. Roofs are blown off homes, while signs, trees and bushes are all blown over. Flooding occurs 3-5 hours before the storm. Major flood damage done to lower floors of coastal buildings. Piers are destroyed. Small boats are moderately damaged. Any areas lower than 10 feet above sea level within six miles of the coast should evacuate.
Category Five
Winds greater than 155 mph (135 kt or 249 km/hr). Storm surge is greater than 18 feet above normal. Small structures are blown over, and many roofs are blown off and away. Mobile homes are completely destroyed. All trees, signs, and bushes are blown over and away. Flooding occurs 3-5 hours before the storm makes landfall. Major damage done to lower floors of all coastal buildings. Piers are destroyed. Small boats are destroyed. Residents within 5-10 miles of the coastline should evacuate.
The Saffir-Simpson Hurricane Scale
http://www.weather.com/encyclopedia/charts/tropical/saffirscale.htmlThis scale was developed in the early 1970s by Herbert Saffir, a consulting engineer in Coral Gables, Florida, and Dr. Robert Simpson, then director of the National Hurricane Center. The scale is based primarily on wind speeds and includes estimates of barometric pressure and storm surge associated with each of the five categories. It is used to give an estimate of the potential property damage and flooding expected along the coast from a hurricane landfall.
Slideshow:
See potential damage per categoryCategory Winds Surge Central Pressure
1 - Minimal 74 - 95 mph or 64 - 82 kts 4 - 5 feet greater than 980 mb or 28.94 in
2 - Moderate 96 - 110 mph or 83 - 95 kts 6 - 8 feet 965 - 979 mb or 28.50 - 28.91 in
3 - Extensive 111 - 130 mph or 96 - 113 kts 9 - 12 feet 945 - 964 mb or 27.91 - 28.47 in
4 - Extreme 131 - 155 mph or 114 - 135 kts 13 - 18 feet 920 - 944 mb or 27.17 - 27.88 in
5 - Catastrophic greater than 155 mph or 135 kts greater than 18 feet less than 920 mb or 27.17 in
Category 1 - Minimal
Damage primarily restricted to shrubbery, trees, and unanchored mobile homes; no substantial damage to other structures; some damage to poorly constructed signs.
Some coastal road flooding and minor pier damage.
Category 2 - Moderate
Considerable damage to shrubbery and tree foliage, some trees blown down; major damage to exposed mobile homes; extensive damage to poorly constructed signs and some damage to windows, doors and roofing materials of buildings, but no major destruction to buildings.
Coastal roads and low-lying escape routes inland cut off by rising water about two to four hours before landfall; considerable damage to piers, marinas flooded; small craft in protected anchorage torn from moorings.
Category 3 - Extensive
Foliage torn from trees; large trees blown down; poorly constructed signs blown down; some damage to roofing, windows, and doors; some structural damage to small buildings; mobile homes destroyed.
Serious flooding along the coast; many small structures near the coast destroyed; larger coastal structures damaged by battering waves and floating debris.
Low-lying escape routes inland cut off by rising water about three to five hours before landfall; flat terrain 5 feet or less above sea level flooded up to 8 or more miles inland.
Evacuation of low-lying residences within several blocks of shoreline may be required.
Category 4 - Extreme
Shrubs, trees, and all signs blown down; extensive damage to roofs, windows, and doors, with complete failure of roofs on many smaller residences; mobile homes demolished.
Flat terrain 10 feet or less above sea level flooded inland as far as 6 miles; flooding and battering by waves and floating debris cause major damage to lower floors of structures near the shore; low-lying escape routes inland cut off by rising water about three to five hours before landfall; major erosion of beaches
Massive evacuation of inland residences as far inland as 6 miles may be required.
Category 5 - Catastrophic
Trees, shrubs, and all signs blown down; considerable damage to roofs of buildings, with very severe and extensive damage to windows and doors; complete failure on many roofs of residences and industrial buildings; extensive shattering of glass in windows and doors; complete buildings destroyed; small building overturned or blown away; mobile homes demolished.
Major damage to lower floors of all structures less than 15 feet above sea level within 1500 feet of the shore.
Low-lying escape routes inland cut off by rising water about three to five hours before landfall; major erosion of beaches.
Massive evacuation of residential areas on low ground as far inland as 10 miles may be required.
[Information from The National Hurricane Center]
Beaufort Wind Scale
Developed in 1805 by Sir Francis Beaufort of England
Force Wind
(Knots) WMO
Classification Appearance of Wind Effects
On the Water On Land
0 Less than 1 Calm Sea surface smooth and mirror-like Calm, smoke rises vertically
1 1-3 Light Air Scaly ripples, no foam crests Smoke drift indicates wind direction, still wind vanes
2 4-6 Light Breeze Small wavelets, crests glassy, no breaking Wind felt on face, leaves rustle, vanes begin to move
3 7-10 Gentle Breeze Large wavelets, crests begin to break, scattered whitecaps Leaves and small twigs constantly moving, light flags extended
4 11-16 Moderate Breeze Small waves 1-4 ft. becoming longer, numerous whitecaps Dust, leaves, and loose paper lifted, small tree branches move
5 17-21 Fresh Breeze Moderate waves 4-8 ft taking longer form, many whitecaps, some spray Small trees in leaf begin to sway
6 22-27 Strong Breeze Larger waves 8-13 ft, whitecaps common, more spray Larger tree branches moving, whistling in wires
7 28-33 Near Gale Sea heaps up, waves 13-20 ft, white foam streaks off breakers Whole trees moving, resistance felt walking against wind
8 34-40 Gale Moderately high (13-20 ft) waves of greater length, edges of crests begin to break into spindrift, foam blown in streaks Whole trees in motion, resistance felt walking against wind
9 41-47 Strong Gale High waves (20 ft), sea begins to roll, dense streaks of foam, spray may reduce visibility Slight structural damage occurs, slate blows off roofs
10 48-55 Storm Very high waves (20-30 ft) with overhanging crests, sea white with densely blown foam, heavy rolling, lowered visibility Seldom experienced on land, trees broken or uprooted, "considerable structural damage"
11 56-63 Violent Storm Exceptionally high (30-45 ft) waves, foam patches cover sea, visibility more reduced
12 64+ Hurricane Air filled with foam, waves over 45 ft, sea completely white with driving spray, visibility greatly reduced
http://www.spc.noaa.gov/faq/tornado/beaufort.htmlFujita Tornado Damage Scale
http://www.spc.noaa.gov/faq/tornado/f-scale.htmlDeveloped in 1971 by T. Theodore Fujita of the University of Chicago
SCALE WIND ESTIMATE *** (MPH) TYPICAL DAMAGE
F0 < 73
Light damage. Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged.
F1 73-112
Moderate damage. Peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos blown off roads.
F2 113-157
Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground.
F3 158-206
Severe damage. Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown.
F4 207-260
Devastating damage. Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated.
F5 261-318
Incredible damage. Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters (109 yds); trees debarked; incredible phenomena will occur.
*** IMPORTANT NOTE ABOUT F-SCALE WINDS: Do not use F-scale winds literally. These precise wind speed numbers are actually guesses and have never been scientifically verified. Different wind speeds may cause similar-looking damage from place to place -- even from building to building. Without a thorough engineering analysis of tornado damage in any event, the actual wind speeds needed to cause that damage are unknown. The
Enhanced F-scale will be implemented February 2007.
藤田级数 (Fujita Scale)http://sciencelinks.jp/ch/content/view/789/261/
“藤田级数”被全球各地广泛用作衡量龙卷风规模的数值指标，是由已经逝世的气象学家、外号“龙卷风博士”的藤田哲也所提出的。龙卷风大小可以通过其风速和大气压来衡量，但是过去并没有类似衡量龙卷风规模的方法。上世纪70年代后期，藤田认为可以利用龙卷风对房屋和自然界物体的破坏程度来衡量风的大小，并制定龙卷风强度和规模的衡量准则，即“藤田级数”。该级数分为6段，分别为F-0至F-5等级。
