Beaufort

Miles per hour

Km per Hour

Land Description

Sailing Description

0

<1

<1.6

Calm: Still: Smoke will rise vertically.

Use the motor

1

1-3

1.6-4.8

Light Air: Rising smoke drifts, weather vane is inactive.

Use the motor

2

4-7

6.4-11.3

Light Breeze: Leaves rustle, can feel wind on your face, weather vane is inactive.

Full main, large jib, boat begins to heel (tilt)

3

8-12

12.9-19.3

Gentle Breeze: Leaves and twigs move around. Light weight flags extend.

FUN! Full main, large jib, boat heels (tilts)

4

13-18

20.9-29.0

Moderate Breeze: Moves branches, raises dust and paper.

GREAT! Full main, large jib, boat making speed

5

19-24

30.6-38.6

Fresh Breeze: Moves trees sway.

Leeward rail near water. Single reef in main, smaller jib

6

25-31

40.2-50.0

Strong Breeze: Large tree branches move, open wires (such as telegraph wires) begin to "whistle", umbrellas are difficult to keep under control.

Sailing is "spirited". Second reef in main

7

32-38

51.5-61.2

Moderate Gale: Large trees begin to sway, noticeably difficult to walk.

Can't sail to windward. Three reefs in main (if possible) working jib

8

39-46

62.8-74.0

Fresh Gale: Twigs and small branches are broken from trees, walking into the wind is very difficult.

Boat's sailing ability is limited. Use motor, seek shelter

9

47-54

75.6-86.9

Strong Gale: Slight damage occurs to buildings, shingles are blown off of roofs.

Run under bare poles, lie ahull, set a sea anchor

10

55-63

88.5-101.4

Whole Gale: Large trees are uprooted, building damage is considerable.

Promise things to any deity you can think of.

11

64-72

103.0-115.9

Storm: Extensive widespread damage.

These typically occur only at sea, and rarely inland. ARGH.