WIND CATEGORY

Beaufort

Designation

Effect on land

Effect on sea

km/h

0stillcalmmirror smoothup to 1
1Light draftSmoke indicates directionSmall ripples1 - 5
2Light breezeWind vanes moveNo marked waves6 - 11
3Weak breezeLeaves moveCrests, and partly whitecaps12 - 19
4Moderate breezeTwigs movePlenty of whitecaps, pennon extended20 - 28
5Fresh breezeBranches and saplings swayWhitecaps everywhere, some spray29 - 38
6Strong windThick branches moveLarge waves, white areas of foam39 - 49
7Stiff windSmall trees moveSea towers up, white strips of foam in the direction of wind50 -61
8Stormy windTwigs torn offHigh mountains of waves, thick strips of foam in direction of wind, spray62 -74
9StormSmall damage to housesAs for Beaufort 875 - 88
10Heavy stormTrees are uprootedVery high seas, visibility impaired by spray89 - 102
11Violent stormSevere damageSea entirely white, air mixed with foam and spray, no visibility103 - 117
12HurricaneDevastation.über 117