FORCE

DESCRIPTION

MPH

EFFECTS

0

Calm

0-1

Land- Smoke rises vertically

Water- Like a mirror

1

Light Air

1-3

L- Rising smoke drifts
W- Small ripples

2

Light
Breeze

4-7

L- Leaves rustle
W- Small wavelets, wind fills sail

3

Gentle Breeze

8-12

L- Light flags extend
W- Large wavelets, sailboats heel

4

Moderate Breeze

13-18

L- Moves thin branches
W- Working breeze, sailboats at hull speed

5

Fresh Breeze

19-24

L- Small trees sway
W- Numerous whitecaps, time to shorten sails

6

Strong Breeze

25-31

L- Large tree branches move
W- Whitecaps everywhere, sailboats head ashore, large waves

7

Moderate Gale

32-38

L- Large trees begin to sway
W- Much bigger waves, some foam, sailboats at harbor

8

Fresh
Gale

39-46

L- Small branches are broken from trees
W- Foam in well marked streaks, larger waves, edges of crests break off

9

Strong
Gale

47-54

L- Slight damage occurs to buildings
W- High waves, dense spray, visibility affected

10

Whole
Gale

55-63

L- Large trees uprooted, considerable building damage
W- Very high waves, heavy sea roll, surface white with spray and foam, visibility impaired

11

Storm

64-74

L- Extensive widespread damage
W- Exceptionally high waves, small to medium ships obscured, visibility poor

12

Hurricane

74+

L- Extreme destruction
W- Waves 40+', air filled with foam and spray, visibility restricted