| Wind Warnings |
| Category |
Description |
| Small Craft Advisory |
Forecast winds of 18 to 33 knots (21 to 38 mph). Small Craft
Advisories may also be issued for hazardous sea conditions
or lower wind speeds that may affect small craft operations. |
| Gale Warning |
Forecast winds of 34 to 47 knots (39 to 54 mph) |
| Storm Warning |
Forecast winds of 48 knots (55 mph) or greater |
| Tropical Storm Warning |
Forecast winds of 48 to 63 knots (55 to 73 mph) associated
with a tropical storm |
| Hurricane Warning |
Forecast winds of 64 knots (74 mph) or higher associated
with a hurricane |
| Beaufort Wind Scale |
| Beaufort
Number |
Wind
Speed |
Description |
Effects
Land / Sea |
| mph |
km/hr |
knots |
| 0 |
<1 |
<1 |
<1 |
Calm |
Still, calm air, smoke will rise
vertically. Water is mirror-like. |
| 1 |
1-3
mph |
1-5
kph |
1-3
knots |
Light Air |
Rising smoke drifts, wind vane is
inactive. Small ripples appear on water surface. |
| 2 |
4-7
mph |
6-11
kph |
4-6
knots |
Light Breeze |
Leaves rustle, can feel wind on your
face, wind vanes begin to move. Small wavelets develop, crests
are glassy. |
| 3 |
8-12
mph |
12-19
kph |
7-10
knots |
Gentle Breeze |
Leaves and small twigs move, light
weight flags extend. Large wavelets, crests start to break,
some whitecaps. |
| 4 |
13-18
mph |
20-28
kph |
11-16
knots |
Moderate Breeze |
Small branches move, raises dust,
leaves and paper. Small waves develop, becoming longer, whitecaps. |
| 5 |
19-24
mph |
29-38
kph |
17-21
knots |
Fresh Breeze |
Small trees sway. White crested wavelets
(whitecaps) form, some spray. |
| 6 |
25-31
mph |
39-49
kph |
22-27
knots |
Strong Breeze |
Large tree branches move, telephone
wires begin to "whistle", umbrellas are difficult
to keep under control. Larger waves form, whitecaps prevalent,
spray. |
| 7 |
32-38
mph |
50-61
kph |
28-33
knots |
Moderate or Near Gale |
Large trees sway, becoming difficult
to walk. Larger waves develop, white foam from breaking waves
begins to be blown. |
| 8 |
39-46
mph |
62-74
kph |
34-40
knots |
Gale or Fresh Gale |
Twigs and small branches are broken
from trees, walking is difficult. Moderately large waves with
blown foam. |
| 9 |
47-54
mph |
75-88
kph |
41-47
knots |
Strong Gale |
Slight damage occurs to buildings,
shingles are blown off of roofs. High waves (6 meters), rolling
seas, dense foam, Blowing spray reduces visibility. |
| 10 |
55-63
mph |
89-102
kph |
48-55
knots |
Whole Gale or Storm |
Trees are broken or uprooted, building
damage is considerable. Large waves (6-9 meters), overhanging
crests, sea becomes white with foam, heavy rolling, reduced
visibility. |
| 11 |
64-72
mph |
103-117
kph |
56-63
knots |
Violent Storm |
Extensive widespread damage. Large
waves (9-14 meters), white foam, visibility further reduced. |
| 12 |
73+
mph |
118+
kph |
64+
knots |
Hurricane |
Extreme destruction, devastation.
Large waves over 14 meters, air filled with foam, sea white
with foam and driving spray, little visibility. |
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