Smoke rises vertically
Smoke drifts with air, weather vanes inactive
Weather vanes active, wind felt on face, leaves rustle
Leaves & small twigs move, light flags extend
Small branches sway, dust & loose paper blows about
Small trees sway, waves break on inland waters
Large branches sway, umbrellas difficult to use
Whole trees sway, difficult to walk against wind
Twigs broken off trees, walking against wind very difficult
Slight damage to buildings, shingles blown off roof
Trees uprooted, considerable damage to buildings
Widespread damage, very rare occurrence
Violent destruction