||Wind Force (Beaufort)
||Probable Wave Height ft
||Sea smooth and mirror- like.
||Scale-like ripples without foam crests.
||Small, short wavelets; crests have glassy appearance and do not break.
||Large wavelets; some crests begin to break; foam of glassy appearance.
Occasional white foam crests.
||Small waves, becoming longer; fairly frequently white foam crests.
||Moderate waves, taking a more pronounced long form; many white foam
crests; there may be some spray.
||Large waves begin to form; white foam crests are more extensive
everywhere; there may be some spray.
||Sea heaps up and white foam from breaking waves begins to be blown in
streaks along the direction of the wind; spindrift begins.
||Moderately high waves of greater length; edges of crests break into
spindrift; foam is blown in well marked streaks along the direction of the wind.
||High waves; dense streaks of foam along the direction of the wind; crests
of waves begin to topple, tumble and roll over; spray may reduce visibility.
||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 is white in appearance. The tumbling of the sea becomes
heavy and shock-like. Visibility is reduced.
||Exceptionally high waves that may obscure small and medium sized ships.
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 is reduced.
||The air is filled with foam and spray. Sea completely white with
driving spray; visibility very much reduced.