Wind Intensity

0 No wind: Queit, smoke straightened upwards

1 Soft wind: Leaves vibrate gently, smoke can represents direction.

2 Gentle wind: Leaves vibrate with gentle noise, wind can be felt.

3 Mild wind: Leaves and branches vibrate incessantly, flag can be unfolded

4 Moderate breeze: blow up tiny dirts, paper scraps, small branches vibrate

5 cool breeze: treelets vibrate sometimes, ribbles can be seen on the lake"s surface

6 Strong wind: Trees vibrate vigorously, wires whirring, difficult in holding up umbrella