OLIMPIADE SAINS NASIONAL 2009 BIDANG ILMU KEBUMIAN

Table 1. Beaufort wind speed scale.BeaufortCodeSpeedMilesper HourSpeedKilometersper HourDescriptionEffects on theEnvironment0 < 1 < 1 calm smoke rises vertically1 2 - 3 1 - 5 light air smoke drifts slowly2 4 - 7 6 - 11 light breeze3 8 - 12 12 - 19 gentle breeze4 13 - 18 20 - 29 moderate breezeleaves rustle, wind can befelt, wind vanes moveleaves and twigs on treesmovesmall tree branches move,dust is picked up from theground surface5 19 - 24 30 - 38 fresh breeze small trees move6 25 - 31 39 - 51 strong breeze7 32 - 38 51 - 61 near galelarge branches move,telephone and poweroverhead wires whistletrees move, difficult to walkin the wind8 39 - 46 62 - 74 gale twigs break off from trees9 47 - 54 75 - 86 strong gale10 55 - 63 87 - 101 whole gale11 64 - 74 102 - 120 storm12 > 75 > 120 hurricanebranches break off from trees,shingles blown off roofstrees become uprooted,structural damage onbuildingswidespread damage tobuildings and treessevere damage to buildingsand trees