Beaufort Scale - Tornado/Hurricane Scales - ROYAL METEOROLOGICAL INSTITUTE

Beaufort Scale of Wind Force
Created in 105 or 106AP by Cruisanan admiral and hydrographer Francis Beaufort (74-157AP)
Wind Force Wind Velocity of ...
and more
Description of Wind Land Criterion Description of Wave Sea Criterion Wave height (m)
Bft No m/s km/h nm/h = kt mph probable maximum
0 0.0 0.0 0 0 Calm Calm; smoke rises vertically. - Sea like a mirror. - -
1 0.3 2.2 1 1 Light airs Direction of wind shown by smoke drift but not by wind vanes. Ripples Ripples with the appearance of scales are formed, but without foam crests. 0.1 0.1
2 1.6 6.5 4 4 Light breeze Wind felt on face; leaves rustle; weather vane moved by wind. Small wavelets Small wavelets, still short but more pronounced. Crests have a glassy appearance and do not break. 0.2 0.3
3 3.4 12.2 7 8 Gentle breeze Leaves and small twigs in constant motion. Wind extends light flags. Large wavelets Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses. 0.6 1.0
4 5.5 19.1 11 13 Moderate breeze Raises dust and loose paper; small branches are moved. Small waves Small waves becoming longer, fairly frequent white horses. 1.0 1.5
5 8.0 27.0 17 19 Fresh breeze Small trees in leaf begin to sway. Crested wavelets form on inland waters. Moderate waves Moderate waves, taking more pronounced long form; many white horses are formed. Chance of some spray. 2.0 2.5
6 10.8 35.6 22 25 Strong breeze Large branches in motion; whistling heard in telegraph wires, umbrellas used with difficulty. Large waves Large waves begin to form; white foam crests are more extensive everywhere. Probably some spray. 3.0 4.0
7 13.9 45.0 28 32 Near Gale Whole trees on motion; inconvenience felt when walking against wind. Large waves Sea heaps up and white foam from breaking waves begins to be blown in streaks. 4.0 5.5
8 15.2 55.1 34 39 Gale Breaks twigs off trees; generally impedes progress. Moderately high waves Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in streaks. 6.0 7.5
9 20.8 65.9 41 47 Severe gale Slight structural damage occurs such as slates removed. High waves High waves. Dense streaks of foam. Crests of waves begin to topple, tumble and roll over. Spray may affect visibilty. 7.0 10.0
10 24.5 77.8 48 55 Storm Seldom experienced inland; trees uprooted; considerable structural damage occurs. Very high waves Very high waves with long overhanging crests. Resulting foam is blown in dense white streaks. The surface takes on a white appearance. Visibility affected. 9.0 12.5
11 28.5 90.7 56 64 Violent storm Very rarely experienced inland; accompanied by widespread damage. Exceptionally high waves Exceptionally high waves. The sea is completely covered with long white patches of foam. Everywhere the edges of wave crests are blown into froth. Visibility affected. 11.5 16.0
12 32.7 104.4 64 74 Hurricane Very rarely experienced; Hurricane accompanied by widespread damage. Exceptionally high waves Air filled with foam and spray. Sea completely white with driving spray. Visibility very severely affected. 14.0 > 16

Some texts and numbers from MarineWeather.Com have been used.

Chakrazipang Tornado Scale (271AP) Utania Hurricane Scale (by HUMOC)
0 Tornado Chakrazipang Scale 0 40-72 mph
minor roof, tree, and sign damage
1 Tornado Chakrazipang Scale 1 73-112 mph 1 Category I Hurricane, Minimal 74-95 mph
roofs damaged; barns torn apart; weak trailers flipped and torn apart; cars thrown from roads; sheet metal buildings destroyed barometer >= 980 mb (hPa), 28.94 inches; storm surge 4-5 ft
damage primarily to shrubbery, trees, foliage, unanchored mobile homes, and small unsecured coverings (i.e. carports). No significant damage to well anchored structures. Some damage to poorly constructed signs. Low lying coastal roads inundated. Minor pier and marina damage. Small craft exposed to open moorings may be torn free
2 Tornado Chakrazipang Scale 2 113-157 mph 2 Category II Hurricane, Moderate 96-110 mph
strongly built schools, homes, and businesses unroofed; concrete block buildings, weak homes, and schools destroyed; trailers disintegrated barometer = 979-965 mb (hPa), 28.91-28.50 inches; storm surge 6-8 ft
considerable damage to foliage and shrubbery, smaller trees uprooted. Major damage to exposed mobile homes. Extensive damage to poorly constructed signs. Possible damage to roofing, windows and doors. No major damage to secure buildings. Coastal roads and low-lying escape routes cut by rising waters 2 to 4 hours prior to storm arrival. Considerable damage to piers. Marinas flooded by storm surge. Small craft in open moorings ripped free from mooring. Evacuation of low-lying areas and shoreline residences required
3 Tornado Chakrazipang Scale 3 158-206 mph 3 Category III Hurricane, Extensive 111-130 mph
strongly built schools, homes, and businesses have outside walls blown away; weaker homes completely swept away barometer = 964-945 mb (hPa), 28.47-27.91 inches; storm surge 9-12 ft
foliage torn from trees; large trees blown down. Practically all poorly constructed signs destroyed. Some damage to roofing and windows that are unbraced. Mobile homes unsecured destroyed. Serious flooding of coastal areas and smaller buildings destroyed along shoreline; larger structures near coast damaged by battering waves and debris. Low-lying escape routes cut by rising water inland 3 to 5 hours before hurricane center arrival. Terrain continuously lower than 5 ft above mean sea level may flood as much as 8 miles or more inland. Evacuation of shoreline and low-lying surrounding area where hurricane is estimated to come ashore may be required to be evacuated
4 Tornado Chakrazipang Scale 4 207-260 mph 4 Category IV Hurricane, Extreme 131-155 mph
strongly built homes have all interior and exterior walls blown apart; cars thrown 300 yards or more in the air barometer = 944-920 mb (hPa), 27.88-27.17 inches; storm surge 13-18 ft
shrubs and trees uprooted; all signs blown down or destroyed. Extensive damage to roofing, windows, and doors. Complete failure of roofs on smaller structures. Complete destruction of mobile homes whether secured or not. Terrain continuously lower than 10 feet above mean sea level may flood requiring massive evacuation of residences as far as 6 miles or more inland. Major damage to lower floors of large structures near shore line due to flooding and debris. Low-lying escape routes will be cut off 3 to 5 hours prior to hurricane center arrival due to flooding from storm surge. Major erosion of beachheads and coastal formations
5 Tornado Chakrazipang Scale 5 261-318 mph 5 Category V Hurricane, Catastrophic >155 mph
strongly built homes are completely blown away barometer < 920 mb (hPa), 27.17 inches; storm surge >18 ft
shrubs and trees blown down and uprooted; considerable damage to roofs of all buildings; all signs down. Very severe and extensive damage to windows and doors. Complete failure of roofs on several residences and industrial buildings. Extensive shattering of glass from pressure variation and blown debris. Some complete building failures. Smaller buildings are overturned or destroyed. Complete destruction of mobile homes. Major damage to lower floors of large structures less than 15 ft above sea level within 750 yards of shore. Low-lying escape routes cut off due to flooding 6 to 8 hours prior to hurricane center arrival. Massive evacuation of residential areas on low-lying ground within 5 to 10 miles of shore may be required with possible extension up to 15 miles inland
Contents of this table from the page of © Kelley L. Ross, Ph.D.


Compiled © by Winfried Schrödter - last update 07 Jul 07 18:25