Beaufort Scale

Scl

Wind Speed (knots)

Weather Condition

Identifying features on land & Sea

0

Less than 0.3

Calm

Smoke rises vertically
Sea like a Mirror

1

0.3 - 1.5

Light air

Smoke indicates wind direction
Ripples on the Sea

2

1.6 - 3.3

Light breeze

Wind vane moves; wind felt on face
Small Wavelets on the Sea

3

3.4 - 5.4

Gentle breeze

Twigs move; light flag extended
Wave crests begin to break

4

5.5 - 7.9

Moderate breeze

Small branches moved; dust raised
Fairly frequent 'White Horses' at Sea

5

8.0 - 10.7

Fresh breeze

Small trees sway; wavelets on inland water
Moderate waves at Sea

6

10.8 - 13.8

Strong breeze

Large branches move - Telephone wires whistle
Foaming crests and some spray at Sea

7

13.9 - 17.1

Near Gale

Whole trees in motion; some resistance when walking
Foam at Sea begins to be blown into streaks

8

17.2 - 20.7

Gale/Fresh gale

Twigs broken off trees; resistance slows walking
Wave crests break into spindrift

9

20.8 - 24.4

Strong gale

Chimney pots and slates may be removed
High waves at Sea with Rolling crests and dense spray

10

24.5 - 28.4

Storm

Considerable structural damage; trees uprooted
Sea appears white with high overhanging waves and streaks of dense foam

11

28.5 - 32.7

Violent storm

Widespread damage; lives endangered
Sea covered in foam patches with waves high enough to hide medium sized vessels and with crests blown into froth - visibility affected

12

Greater than 32.7

Hurricane

Catastrophic damage; loss of life
Sea completely white with driving spray - Air filled with foam & spray - visibility seriously impaired