Beaufort force 11. Sustained wind speeds in the range of 56 to 63 knots. Exceptionally high waves (long 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 foam; visibility affected. Back to the top

a violent weather condition with winds 64-72 knots (11 on the Beaufort scale) and precipitation and thunder and lightening

Wind with a speed between 56 and 63 knots.