Beaufort scale

The Beaufort scale classifies wind force from observed effects on the sea and land. Its numbered levels correspond to ranges of wind speed.

Beaufort number: A numbered category on the Beaufort scale, representing a range of wind force and speed. Each Beaufort number pairs a speed interval with characteristic effects.
Francis Beaufort: A British naval officer who devised the wind-force scale later named after him. His system made wind descriptions more consistent in naval logs.
Maritime safety: Practices and systems intended to reduce hazards to people, ships, and operations at sea. Beaufort descriptions communicate conditions that can affect vessel safety.
Saffir–Simpson scale: A five-category scale for classifying tropical cyclones by sustained wind speed. Unlike Beaufort, it classifies tropical cyclones rather than ordinary wind force.
Wind speed: The rate at which air moves relative to a reference point. The scale's descriptive levels correspond to wind-speed ranges.
Royal Navy: The United Kingdom's naval warfare and maritime service. The scale was developed for describing sailing conditions in naval service.
Marine weather forecast: A prediction of weather conditions over a specified sea area and period. Forecasts often use Beaufort force to summarize expected winds.
Fujita scale: A scale estimating tornado intensity from damage to buildings and vegetation. Both use observed effects, but the Fujita scale assesses tornado damage after an event.
Sea state: A description of the condition of the sea surface, including waves and swell. Wave height and appearance provide key observations for assigning marine Beaufort levels.
HMS Beagle: A British naval survey ship that carried Charles Darwin on his voyage around the world. Beaufort's scale gained wider use through its adoption aboard this surveying vessel.

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