Beaufort Wind Scale

Beaufort
Force

Wind speed
Knots

Description

Sea Condition

0

0

Calm

Sea like a mirror

1

1 - 3

Light Air

Ripples but without foam crests

2

4 - 6

Light Breeze

Small wavelets. Crests do not break

3

7 - 10

Gentle Breeze

Large wavelets. Perhaps scattered white horses

4

11 - 16

Moderate Breeze

Small waves. Fairly frequent white horses.

5

17 - 21

Fresh Breeze

Moderate waves, many white horses

6

22 - 27

Strong Breeze

Large waves begin to form; white foam crests, probably spray

7

28 - 33

Near Gale

Sea heaps up and white foam blown in streaks along the direction of the wind

8

34 - 40

Gale

Moderately high waves, crests begin to break into spindrift

9

41 - 47

Strong Gale

High waves. Dense foam along the direction of the wind. Crests of waves begin to roll over. Spray may affect visibility

10

48 - 55

Storm

Very high waves with long overhanging crests. The surface of the sea takes a white appearance. The tumbling of the sea becomes heavy and shock like. Visibility affected

11

56 - 63

Violent Storm

Exceptionally high waves. The sea is completely covered with long white patches of foam lying in the direction of the wind. Visibility affected

12

64+

Hurricane

The air is filled with foam and spray. Sea completely white with driving spray. Visibility very seriously affected.

Saffir - Simpson Hurrican Scale

Category

Descr.

m/s

km/h

Knots

floot
over normal

pression

1

weak

35-45

119-153

65-83

1.2-1.5 m

> 980 hPa

2

moderate

46-51

154-177

84-95

1.6-2.4 m

965-980 hPa

3

strong

52-61

178-209

96-113

2.5-3.7 m

945-964 hPa

4

very strong

62-72

210-249

114-134

3.8-5.5 m

920-944 hPa

5

devastating

> 72

> 249

> 134

> 5.5 m

< 920 hPa

Fujita Tornado Scale

Category

Descr.

m/s

km/h

Knots

F 0

gale tornado

19-33

68-121

35-62

F 1

moderate tornado

34-52

122-189

63-97

F 2

significant tornado

53-73

190-264

98-136

F 3

severe tornado

74-97

265-348

137-179

F 4

devastating tornado

98-122

349-439

180-226

F 5

incredible tornado

123-149

440-537

227-276

F 6

inconceivable tornado

> 149

> 537

> 276