Great Storm of 1987 from Portland Bill, Dorset to Cromer, Norfolk the return period of the respective gusts were under 10 years. Sustained winds speeds greater than 75 mph were recorded for over an hour in southern Britain. According to the Beaufort scale of wind intensities, this storm had winds of hurricane force 12 (73 mph or greater); as the term "hurricane" refers to tropical cyclones originating in the North Atlantic or North Pacific, the descriptor "great storm" has tended to be reserved for those storms in recent years reaching this velocity. Hurricanes have a very different wind profile and distribution from storms, and
Beaufort scale responsible for this and for the addition of the land-based descriptors. The measure was slightly altered some decades later to improve its utility for meteorologists. Today, many countries have abandoned the scale and use the metric system based units, m/s or km/h, instead, but the severe weather warnings given to the public are still approximately the same as when using the Beaufort scale. The Beaufort scale was extended in 1946, when forces 13 to 17 were added. However, forces 13 to 17 were intended to apply only to special cases, such as tropical cyclones. Nowadays, the extended scale is only