in gale Maritime Topics On Stamps:

Windforce Scale !


  Windforce: Beaufort scale,
  Description - sea surface: Peterson.

Wind force 0 :
Wind speed:
0,0001 kn, 0 - 0,2 m/s, 0 - 1 km/h
Notation: Calm
Description: mirror like sea, only swell
Wind force 0
Wind force 1
Wind force 1 :
Wind speed:
1...3 kn, 0,3 - 1,5 m/s, 1 - 5 km/h
Notation: Light Air
Description: Ripples with the appearance of scales

Wind force 2 :
Wind speed:
4...6 kn, 1,6 - 3,3 m/s, 6 - 11 km/h
Notation: Light Breeze
Description: Small wavelets, crest of glassy appearance, not breaking
Wind force 2
Wind force 3
Wind force 3 :
Wind speed:
7...10 kn, 3,4 - 5,4 m/s, 12 - 19 km/h
Notation: Gentle Breeze
Description: Large wavelets, crests begin to break, scattered with whitecaps

Wind force 4 :
Wind speed:
11...15 kn, 5,5 - 7,9 m/s, 20 - 28 km/h
Notation: Moderate Breeze
Description: Small waves, becoming longer, numerous whitecaps
Wind force 4
Wind force 5
Wind force 5 :
Wind speed:
16...21 kn, 8,0 - 10,7 m/s, 29 - 38 km/h
Notation: Fresh Breeze
Description: Long waves with many whitecaps, sometimes spray

Wind force 6 :
Wind speed:
22...27 kn, 10,8 - 13,8 m/s, 39 - 49 km/h
Notation: Strong Breeze
Description: Larger waves forming, whitecaps everywhere, more spray
Wind force 6
Wind force 7
Wind force 7 :
Wind speed:
28...33 kn, 13,9 - 17,1 m/s, 50 - 61 km/h
Notation: Near Gale
Description: Sea heaps up, white foam from breaking waves begins to blow in streaks

Wind force 8 :
Wind speed:
34...40 kn, 17,2 - 20,7 m/s, 62 - 74 km/h
Notation: Fresh Gale
Description: Moderately high waves of greater length, edges of crests begin to break into spindrift, foam is blown into wellmarked streaks
Wind force 8
Wind force 9
Wind force 9 :
Wind speed:
41...47 kn, 20,8 - 24,4 m/s, 75 - 88 km/h
Notation: Strong Gale
Description: High waves, seas begins to roll, dense streaks of foam, spray may reduce visibility

Wind force 10 :
Wind speed:
48...55 kn, 24,5 - 28,4 m/s, 89 - 102 km/h
Notation: Whole Gale
Description: Very high waves with overhanging crests, sea takes white appearance as foam is blown in very dense streaks, rolling is heavy and visibility is reduced
Wind force 10
Wind force 11
Wind force 11 :
Wind speed:
56...63 kn, 28,5 - 32,6 m/s, 103 - 117 km/h
Notation: Storm
Description: Exceptionally high waves, sea covered with white foam patches, visibility still more reduced

Wind force 12 :
Wind speed:
>64 kn, >32,7 m/s, >117 km/h
Notation: Hurricane
Description: Air filled with foam, sea completely white with driving spray, visibility still more reduced
Wind force 12


At Wind force 12 the Beaufort scale ends. Strong tropical cyclones, hurricanes, tornados and 'El Nino' made a new scale necessary. So the Saffir-Simpson scale by categories was developped.

In 1949 also the Beaufortla was expanded by five hurricane levels :
Wind force 12 : Wind speed : 118 - 133 km/h;   instead of > 117
Wind force 13 : Wind speed : 134 - 149 km/h
Wind force 14 : Wind speed : 150 - 166 km/h
Wind force 15 : Wind speed : 167 - 183 km/h
Wind force 16 : Wind speed : 184 - 202 km/h
Wind force 17 : Wind speed : > 202 km/h

Hurricane
Saffir - Simpson Scale
Status Winds knots Winds mph Pressure Storm Surge
Depression <35 kn> <38 mph> ------> -----
Tropical Storm 35-63 kn 38-73 mph ------ -----
Category 1 64-82 kts 74-95 mph 966 mb> 4 - 5 ft
Category 2 83-95 kts 96-110 mph 980-965 mb 6 - 8 ft
Category 3 96-113 kts 111-130 mph 964-945 mb 9 - 12 ft
Category 4 114-135 kts 131-155 mph 944-920 mb 13 - 18 ft
Category 5 136 kts+ 156 mph+ <920 mb> >18 ft
This table was taken from the 'Hurricane Watch Net', http://www.hwn.org
Tornado

Specially for Tornados the Fujita Scale was developed:

Fujita Scale
F-Scale NumberIntensity PhraseWind SpeedType of Damage Done
F0Gale tornado40-72 mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards.
F1Moderate tornado73-112 mph The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.
F2Significant tornado113-157 mph Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.
F3Severe tornado158-206 mph Roof and some walls torn off well constructed houses; trains overturned; most trees in fores uprooted
F4Devastating tornado207-260 mph Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.
F5Incredible tornado261-318 mph Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged.
F6Inconceivable tornado319-379 mph These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever achieved, evidence for it might only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies
This table was taken from the 'The Fujita Scale', http://www.tornadoproject.com/fscale/fscale.htm



Have a look to our State-of-the-Sea table!

and on our Stormy Seas page.

© 1998 - 2007 Bjoern Moritz, all rights reserved.

  up - top
  next page
  back
  menu page
  home, first page