Cumulonimbus and aviation at this altitude, updraughts with speeds that can exceed . Such an updraught speed corresponds to the wind speed of a small hurricane. The speed can even exceed . The maximum number in the Beaufort scale is 12 ("hurricane force" wind) and is assigned to wind speeds of 64 knots or greater. If the Beaufort scale were extended, these updraughts would have a Beaufort number of 14 "in the vertical direction". The turbulence is then "extreme" at this altitude. Moreover, the diameters of the updraught columns vary between 2 km (air mass thunderstorm) and 10 km (supercell thunderstorm). The height
Wind gale-force winds lie between and with preceding adjectives such as moderate, fresh, strong, and whole used to differentiate the wind's strength within the gale category. A storm has winds of to . The terminology for tropical cyclones differs from one region to another globally. Most ocean basins use the average wind speed to determine the tropical cyclone's category. Below is a summary of the classifications used by Regional Specialized Meteorological Centers worldwide: The Enhanced Fujita Scale (EF Scale) rates the strength of tornadoes in the United States based on the damage they cause. Below is the scale. The station model