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Beaufort Wind Scale

In 1805, Francis Beaufort conceived a scale of classification of the strength of the wind, numbered from 0 to 12 degrees.
This scale, initially intended to improve the precision of the newspapers of edge, is of a universal use in marine meteorology today.

FORCE	APPELLATION	VITESSE DU VENT		ÉTAT DE LA MER	EFFETS À TERRE
FORCE	APPELLATION	Noeud	Km/h	ÉTAT DE LA MER	EFFETS À TERRE
0	Calm	1	1	Sea like a mirror	Calm. Smoke rises vertically.
1	Light air	1 to 3	1 to 5	Ripples with the appearance of scales are formed, but without foam crests	Smoke drift indicates wind direction. Leaves and wind vanes are stationary.
2	Light breeze	4 to 6	6 to 11	Small wavelets, still short bute more pronounced ; crests have a glassy appearance and do not break	Wind felt on exposed skin. Leaves rustle.Wind vanes begin to move.
3	Gentle breeze	7 to 10	12 to 19	Large wavelets. Crests begin to break ; scattered whitecaps	Leaves and small twigs constantly moving, light flags extended.
4	Moderate breeze	11 to 16	20 to 28	Small waves with breaking crests. Fairly frequent whitecaps.	Dust and loose paper raised. Small branches begin to move.
5	Fresh breeze	17 to 21	29 to 38	Moderate waves of some length. Many whitecaps. Small amount of spray.	Branches of moderate size move. Small trees in leaf begin to sway.
6	Strong breeze	22 to 27	39 to 49	Long waves begin to form. White foam crests are very frequent. Some airborne spray is present.	Large branches in motion. Whistling heard in overhead wires. Umbrella use becomes difficult. Empty plastic bins tip over.
7	High Wind, moderate gale, near gale	28 to 33	50 to 61	Sea heaps up. Some foam from breaking waves is blown into streaks along wind direction. Moderate amounts of airborne spray.	Whole trees in motion. Effort needed to walk against the wind.
8	Gale, fresh gale	34 to 40	62 to 74	Moderately high waves with breaking crests forming spindrift. Well-marked streaks of foam are blown along wind direction. Considerable airborne spray.	Some twigs broken from trees. Cars veer on road. Progress on foot is seriously impeded.
9	Strong/severe gale	41 to 47	75 to 88	High waves whose crests sometimes roll over. Dense foam is blown along wind direction. Large amounts of airborne spray may begin to reduce visibility.	Some branches break off trees, and some small trees blow over. Construction/temporary signs and barricades blow over.
10	Storm, whole gale	48 to 55	89 to 102	Very high waves with overhanging crests. Large patches of foam from wave crests give the sea a white appearance. Considerable tumbling of waves with heavy impact. Large amounts of airborne spray reduce visibility.	Trees are broken off or uprooted, structural damage likely.
11	Violent storm	56 to 63	103 to 117	Exceptionally high waves. Very large patches of foam, driven before the wind, cover much of the sea surface. Very large amounts of airborne spray severely reduce visibility.	Widespread vegetation and structural damage likely.
12	Hurricane force	64 and +	118 and +	Huge waves. Sea is completely white with foam and spray. Air is filled with driving spray, greatly reducing visibility.	Severe widespread damage to vegetation and structures. Debris and unsecured objects are hurled about.