Maximum sustained wind 50% of the geostrophic wind speed aloft; while over open water or ice, the reduction is between 10% and 30%. In most basins, maximum sustained winds are used to define their category. In the Atlantic and northeast Pacific oceans, the Saffir–Simpson scale is used. This scale can be used to determine possible storm surge and damage impact on land. In most basins, the category of the tropical cyclone (for example, tropical depression, tropical storm, hurricane/typhoon, super typhoon, depression, deep depression, intense tropical cyclone) is determined from the cyclone's maximum sustained wind. Only in Australia is this quantity not used to
Winter storm naming in the United Kingdom and Ireland predicted large-scale, cyclonic windstorms with potential for significant land-based wind impacts. This may result in names being allocated to events that are below the traditional Beaufort scale definition of a storm. A storm will be named when it is deemed able to have a "substantial" impact on the UK or Ireland. Met Éireann names any storm which triggers a status Orange or Red weather warning focusing on wind, though consideration was also given to rain and snow events in 2016–17. The basis for such as outlined on their weather warning service are mean wind speeds in excess of 40 mph