Beaufort scale of wind force

This is a very important document conserning the weather. You should read it and study carefully the categorization. Sometimes you will need to inform the coastal guard or other vessels about the situation in which you are and you will have to refer to this scale.
Column 1 is the Beaufort Number or Force Number.
Column 2 is the range of wind speeds in knots, measured at a height of 33 feet above sea level.
Column 5 is the probable height of waves in feet in the open sea, remote from land. In enclosed waters, or when near land with an offshore wind, wave heights will be smaller and the waves steeper.
Column 6 is the probable maximum wave height in feet in the open sea (the caveats for column 5 apply here as well)

Force Number	Wind speed (knots)	Standard description	Sea Criteria	(5)	(6)
0	<1	Calm	Sea like a mirror.	-	-
1	1-3	Light air	Ripples with the appearance of scales are formed but without foam crests.	¼	-
2	4-6	Light breeze	Small wavelets, still short but more pronounced. Crests have a glassy appearance and do not break.	½	1
3	7-10	Gentle breeze	Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses.	2	3
4	11-16	Moderate breeze	Small waves, becoming longer; fairly frequent horses.	3 ½	5
5	17-21	Fresh breeze	Moderate waves, taking a more pronounced long form; many white horses are formed. (Chance of some spray.)	6	8 ½
6	22-27	Strong breeze	Large waves begin to form; the white foam crests are more extensive everywhere. (Probably some spray.)	9 ½	13
7	28-33	Near gale	Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.	13 ½	19
8	34-40	Gale	Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in well-marked streaks along the direction of the wind.	18	25
9	41-47	Strong gale	High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble, and roll over. Spray may affect visibility.	23	32
10	48-55	Storm	Very high waves with long overhanging crests. The resulting foam in great patches is blown in dense white streaks along the direction of the wind. On the whole the surface of the sea takes a white appearance. The tumbling of the sea becomes heavy and shocklike. Visibility affected.	29	41
11	56-63	Violent storm	Exceptionally high waves. (Small and medium-sized ships might be for a time lost to view behind the waves.) The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility affected.	37	52
12	64+	Hurricane	The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected.	45	-