Beaufortova větrná stupnice

 

  Rychlost větru  
Force Popis m/s km/h uzly mil/h Land Signs Sea State
0 Calm 0 – 0.4 0 - 1.4 0 - 0.8 0 - 0.9 Smoke rises vertically Mirror Smooth
1 Light Air 0.42 – 1.1 1.5 – 4 0.9 - 2 1 – 3 Smoke Drifts Scaly Ripple
2 Light Breeze 1.4 – 3 5 - 11 2 – 5 4 – 7 Leaves rustle, wind vane moves Small wavelets, crests do not break
3 Gentle Breeze 3.3 – 5.5 12 – 20 6 – 9 8 – 12 Light flag will wave, small twigs and leaves move constantly Large wavelets, crests may break
4 Moderate Breeze 5.8 – 8 21 - 29 10 – 14 13 - 18 All flags extended, small branches move, dust and paper blow about Small waves some white horses
5 Fresh Breeze 8.3 – 10.8 30 - 39 15 - 20 19 - 24 Small trees begin to sway Moderate waves, many white horses
6 Strong Breeze 11.1 – 13.9 40 - 50 21 - 26 25 - 31 Large branches move Large waves with foam crests
7 Moderate Gale 14.2 – 16.9 51 - 61 27 - 32 32 - 38 Walking into wind difficult, whole trees move White foam from breaking waves blown in streaks
8 Fresh Gale 17.2 – 20.5 62 - 74 33 - 40 39 - 46 Twigs break from trees, walking difficult High long waves Spindrift
9 Strong Gale 20.8 – 24.2 75 - 87 41 - 47 47 - 54 Root and fence damage High waves, dense streaks of foam
10 Fierce Gale 24.4 – 28 88 - 101 48 - 54 55 - 63 Trees uprooted, structural damage Sea white, violent waves
11 Storm 28.3 – 33.6 102 - 121 55 - 65 64 - 75 May cause widspread damage, rare inland  
12 Hurricane 33.9+ 122+ 66+ 76+ Causes devastation.