Beaufort wind scale and conditions on land and sea

Severn boating

The Beaufort Wind Scale and Velocity Conversions with descriptions for Land and Sea

Force	Description	Knots	mph	km/h	Wave Ht	Sea Description	On Land
0	Calm	< 1	< 1	< 1	-	Sea like a mirror	Smoke rises vertically
1	Very Light	1-3	1-3	1-5	0.1m	Ripples	Smoke drifts
2	Light breeze	4-6	4-7	6-11	0.2m	Small wavelets	Wind felt on face. Rustles leaves
3	Gentle breeze	7-10	8-12	12-19	0.6m	Wave crests begin to break	Leaves and flags move
4	Moderate breeze	11-16	13-18	20-29	1.0m	Small waves frequent white crests	Paper blown about. Small branches move
5	Fresh breeze	17-21	19-24	30-39	2.0m	Moderate waves. Many white crests	Large branches sway
6	Strong breeze	22-27	25-31	40-50	3.0m	Large waves. White foam crests	Small trees sway
7	Near gale	28-33	32-38	51-61	4.0m	Sea heaps up white foam in streaks	Large trees sway. Difficult to walk
8	Gale	32-40	39-46	62-74	5.5m	Moderate high waves breaking crests foam streaks	Small trees blown down
9	Strong gale	41-47	47-54	75-87	7.0m	High waves dense foam streaks	Structural damage. Chimney pots removed
10	Storm	48-55	55-63	88-101	9.0m	Very high waves. Sea surface appears white	Trees uprooted. Much structural damage
11	Violent storm	56-63	64-73	102-117	11.5m	Exceptional high waves sometimes concealing small ships	Widespread damage
12	Hurricane	> 64	>74	>119	14+m	Air filled with foam and spray. Sea white	Widespread damage

Yachtsman, small boat sailors and skippers of motor cruisers should note with caution, the wide range of wind velocities covered by the word 'breeze'. For most pleasure sailors a 'fresh breeze' (Force 5) will prove demanding especially if the wind is against tide!