| SCALE
|
Wind Speed
(MPH) |
Seaman's
Term |
Effects On
Land |
| 0 |
< 1 |
Calm |
Calm; smokes rises vertically |
| 1 |
1 - 3 |
Light Air |
Smoke drift indicates wind direction;
weather vanes do not move |
| 2 |
4 - 7 |
Light Breeze |
Wind felt on face; leaves rustle; wind
vanes begin to move |
| 3 |
8 - 12 |
Gentle Breeze |
Leaves and small twigs in constant
motion; light flags extended |
| 4 |
13 - 18 |
Moderate Breeze |
Dust, leaves and loose paper raised
up; small branches move |
| 5 |
19 - 24 |
Fresh Breeze |
Small, leaved trees begin to sway;
crested wavelets form on inland waters |
| 6 |
25 - 31 |
Strong Breeze |
Large branches of trees in motion;
whistling heard in overhead wires |
| 7 |
32 - 38 |
Moderate Gale |
Whole trees in motion; resistance felt
in walking against wind |
| 8 |
39 - 46 |
Fresh Gale |
Twigs and small branches broken off
trees |
| 9 |
47 - 54 |
Strong Gale |
Slight structural damage occurs; slate
blown from roofs |
| 10 |
55 - 63 |
Whole Gale |
Seldom experienced on land; trees
broken; structural damage occurs |
| 11 |
64 - 72 |
Storm |
Very rarely experienced on land;
usually with widespread damage |
| 12 |
73 + |
Hurricane |
Violence and destruction |