Oceanography

Beaufort scale

Beaufort Wind Scale and Sea State Chart

Sea State	Beaufort Number	Terminology	Wind Speed (miles per hour)	Average Wave Height (feet)	Description
0	0	Calm	0-1	0	Sea like a mirror
1	1	Light air	1-3	0.005	Ripples with appearance of scales; no crests
2	2	Light breeze	4-7	0.18	Small wavelets; crests have glossy appearance but do not break.
3	3	Gentle breeze	8-12	0.19-1	Large wavelets, crests begin to break; foam of glossy appearance; a few white horses.
	4	Moderate breeze	13-18	2-3	Small waves becoming longer form; many white horses formed; some spray
4	5	Fresh breeze	19-24	4-5	Moderate waves taking longer form; many white horses formed; some spray
	6	Strong breeze	25-31	6-10	Large waves begin to form; many white crests more spray
	7	Moderate gale	32-38	11-16	Sea heaps up; white foam from breaking waves begins to be blown in streaks
5	8	Fresh gale	39-46	17-28	Moderately high waves of greater length; edges of crests begin to break into spindrift; foam blown in well marked streaks spray affects visibility.
	9	Strong gale (storm)	47-54	29-40	High waves; dense streaks of foam along wind direction; sea begins to roll; visibility affected
	10	Whole gale (heavy storm)	55-63	41-59	Very high waves with long overhanging crests; sea takes white appearance; rolling heavy; visibility affected.
	11	Violent storm	64-72	60-73	Exceptionally high waves; small and medium sized ships lost from view; crests blown into froth.
	12	Hurricane	73-82	74-80	Air filled with foam and spray; sea completely white with driving spray; visibility very seriously affected.