Beaufort scale used in Taiwan and mainland China, which are often affected by typhoons. Internationally, WMO Manual on Marine Meteorological Services (2012 edition) defined the Beaufort Scale only up to force 12 and there was no recommendation on the use of the extended scale. Wind speed on the 1946 Beaufort scale is based on the empirical relationship: Where "v" is the equivalent wind speed at 10 metres above the sea surface and "B" is Beaufort scale number. For example, "B" = 9.5 is related to 24.5 m/s which is equal to the lower limit of "10 Beaufort". Using this formula the highest
Burns' Day Storm the Netherlands and Belgium. The strongest sustained winds recorded were between 70 and 75 mph (110–120 km/h), comparable to a weak Category 1 hurricane or Hurricane-force 12 on the Beaufort Scale. Strong gusts of up to 104 mph (170 km/h;) were reported, and it was these which caused the most extensive damage. The Burns' Day Storm of 1990 has been given as an example of when the Met Office "got the prediction right". The model forecast hinged on observations from two ships in the Atlantic near the developing storm the day before it reached the UK. During the day of