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
Royal Charter Storm wind speed and a shift in its direction. There was extensive structural damage along the coasts of Devon and Cornwall. The storm drifted northwards, hitting Anglesey by about 8 p.m. and not reaching maximum force at the River Mersey until midday on 26 October, then continued northwards to affect Scotland. The winds reached force 12 on the Beaufort scale and were well over . At the Mersey a wind force of 28 lbs to the square foot (14 N per 100 mm) was measured, more than ever previously recorded. On the north coast of Anglesey, where the "Royal Charter", a