| 0 |
Less than 1 |
Less than 1 |
Calm |
Sea surface like a mirror, but not necessarily flat. |
Smoke rises vertically. |
| 1 |
1 - 5 |
1 - 3 |
Light air |
Ripples with the appearance of scales are formed, but without foam crests. |
Direction of wind shown by smoke drift, but not wind vanes. |
| 2 |
6 - 11 |
4 - 6 |
Light breeze |
Small wavelets, still short but more pronounced. Crests do not break. When visibility good, horizon line always very clear. |
Wind felt on face. Leaves rustle. Ordinary vane moved by wind. |
| 3 |
12 - 19 |
7 - 10 |
Gentle breeze |
Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered whitecaps. |
Leaves and small twigs in constant motion. Wind extends light flag. |
| 4 |
20 - 28 |
11 - 16 |
Moderate breeze |
Small waves, becoming longer. Fairly frequent whitecaps. |
Raises dust and loose paper. Small branches are moved. |
| 5 |
29 - 38 |
17 - 21 |
Fresh breeze |
Moderate waves, taking a more pronounced long form. Many whitecaps are formed. Chance of some spray. |
Small trees with leaves begin to sway. Crested wavelets form on inland waters. |
| 6 |
39 - 49 |
22 - 27 |
Strong breeze |
Large waves begin to form. The white foam crests are more extensive everywhere. Probably some spray. |
Large branches in motion. Whistling heard in telephone wires. Umbrellas used with difficulty. |
| 7 |
50 - 61 |
28 - 33 |
Near gale |
Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind. |
Whole trees in motion. Inconvenience felt in walking against wind. |
| 8 |
62 - 74 |
34 - 40 |
Gale |
Moderately high waves of
greater length. Edges of crests begin to break into the spindrift. The
foam is blown in well-marked streaks along the direction of the wind. |
Breaks twigs off trees. Generally impedes progress. Walking into wind almost impossible. |
| 9 |
75 - 88 |
41 - 47 |
Strong gale |
High waves. Dense streaks
of foam along the direction of the wind. Crests of waves begin to
topple, tumble and roll over. Spray may affect visibility. |
Slight structural damage occurs, e.g. roofing shingles may become loose or blow off. |
| 10 |
89 - 102 |
48 - 55 |
Storm |
Very high waves with long
overhanging crests. Dense white streaks of foam. Surface of the sea
takes a white appearance. The tumbling of the sea becomes heavy and
shock-like. Visibility affected. |
Trees uprooted. Considerable structural damage occurs. |
| 11 |
103 - 117 |
56 - 63 |
Violent storm |
Exceptionally high waves. Sea completely covered with long white patches of foam. Visibility affected. |
Widespread damage. |
| 12 | 118 - 133 | 64 - 71 | Hurricane | Air filled with foam and spray. Sea entirely white with foam. Visibility seriously impaired. | Rare. Severe widespread damage to vegetation and significant structural damage possible. |
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