Beaufort Wind Scale
Beaufort scale, also known as Beaufort wind force scale, was discovered in 1805 by Commander (later Admiral and Knight Commander of the Bath) Francis Beaufort of the British navy for classifying and observing the wind force at sea. The Beaufort scale is used to measure and detail the consequences of different wind speeds on objects on land or at sea.
The Beaufort numbers in the Beaufort scale are arranged from 0 to 12 to represent the wind strength from calm (force 0) to the hurricane ( force 12). The Beaufort scale was further extended in 1946 when forces 13 to 17 were added. The force 13 to 17 are applied only to special cases such as tropical cyclones. The extended scale is only used in Taiwan and Mainland China, which are often affected by typhoons.
What is Beaufort Scale?
The Beaufort scale is used to measure the speed of the wind. It is based on observations rather than actual measurements. It is widely used to measure wind speed today. There are 12 levels, including 0 for “ no wind” in the wind force scale introduced by Beaufort. The level in the Beaufort scale was further extended from 13 to 17 in 1946. All of them were labeled as hurricanes. The further ranges of scale were only used in special cases by China and Taiwan still because they often have typhoons.
Beaufort Scale Definition
Beaufort scale, a wind force scale ranging from 0 ( calm ) to 12 ( hurricane) is an empirical measure for describing the wind speed based on the observed sea conditions.
Wind Scale Beaufort
The wind scale by Beaufort is neither exact nor objective, rather it was based on the visual and subjective observation of a ship and of the sea. The corresponding wind speeds are identified later, but the values in different units were never made equal.
The Beaufort wind force scale is widely used in countries like Hong Kong, Netherlands, Greece, China, Taiwan, Germany, Malta, and Macau, although with some differences between them. Taiwan uses the wind scale with the extension to 17. On 15 May 2006, China started using this extended version of scale without prior notice, and the extended version of the scale was instantly put to use for Typhoon Chanchu. However, Hong Kong and Macau use force 12 as the maximum.
The Beaufort Wind Force Scale Table
Did You Know?
The Beaufort scale is most widely used to measure wind speed today.
The Beaufort scale is named for Sir Francis Beaufort of the British Royal Navy.
The Douglas Sea Scale and the Douglas Wind Scale are similar to the Beaufort scale, but they separate the sea from the wind.
The Beaufort scale was first officially used by HMS Beagle.
The Beaufort scale is a method of measuring wind speed based on the general condition of the surface of a large body of water in terms of wind waves and swell.
The official name of the Beaufort scale is “ Beaufort Wind Force Scale”.
FAQs on Beaufort Scale
1. What is the Beaufort Scale?
The Beaufort Scale is an empirical measure used to estimate wind speed based on visual observations of the wind's effects on the environment, particularly on the sea and on land. It ranges from 0 (calm) to 12 (hurricane force), allowing people, especially sailors, to gauge wind strength without relying on mechanical instruments.
2. Who invented the Beaufort Scale and why?
The scale was developed in 1805 by Sir Francis Beaufort, an Irish hydrographer and officer in the British Royal Navy. He created it to standardise wind observations at sea, enabling sailors to communicate wind conditions consistently by describing the sea state (e.g., calm, ripples, large waves) rather than using subjective terms.
3. How does the Beaufort Scale work without using instruments?
The Beaufort Scale works by correlating visual clues with a specific wind force number. Instead of measuring speed directly, an observer looks at environmental indicators. For example, at sea, they observe the wave patterns, while on land, they might look at how smoke drifts, leaves rustle, or trees sway. Each level on the scale has a corresponding set of observable conditions.
4. What do the numbers on the Beaufort Scale mean?
Each number on the Beaufort Scale, from 0 to 12, represents a specific range of wind speed and a set of observable conditions. For instance:
Force 0 (Calm): Smoke rises vertically; the sea is like a mirror.
Force 4 (Moderate Breeze): Dust and loose paper are raised; small branches move.
Force 7 (Near Gale): Whole trees are in motion; it's difficult to walk against the wind.
Force 12 (Hurricane): Widespread and severe damage occurs.
5. What are some examples of visual clues used for the Beaufort Scale on land?
On land, the Beaufort Scale uses various visual clues to estimate wind force. Key examples include:
Force 1: Smoke drift indicates wind direction, but weather vanes do not move.
Force 3: Leaves and small twigs are in constant motion; light flags are extended.
Force 6: Large branches sway; umbrellas are used with difficulty; whistling is heard in telegraph wires.
Force 9: Slight structural damage occurs (e.g., chimney pots and slates removed).
6. Why is the Beaufort Scale still relevant today, especially for sailors?
The Beaufort Scale remains highly relevant because it does not depend on technology, which can fail at sea. It provides a quick, reliable method for sailors to assess sea state and wind strength, crucial for safe navigation and decision-making. It standardises communication, ensuring that a "strong breeze" means the same thing to sailors everywhere, which is vital for safety warnings and coordinating vessel movements.
7. How does the Beaufort Scale differ from the Saffir-Simpson Scale used for hurricanes?
The primary difference lies in their purpose and measurement. The Beaufort Scale is an observational scale for general wind strength from calm to hurricane force, based on visual effects on sea and land. In contrast, the Saffir-Simpson Hurricane Wind Scale is a more specific, 1-to-5 rating based solely on a hurricane's measured maximum sustained wind speed. It is used to estimate potential property damage from a hurricane, while the Beaufort Scale is a broader tool for everyday wind assessment.
8. What are the main limitations of using the Beaufort Scale for measuring wind speed?
The main limitation of the Beaufort Scale is its subjectivity. Since it relies on human observation, assessments can vary between individuals. Its accuracy is lower than that of an anemometer (a wind-measuring instrument). Furthermore, the visual indicators for land are different from those at sea, and the scale is less reliable in sheltered or urban areas where wind patterns are disrupted by buildings and terrain.
9. Can the Beaufort Scale be used to predict the weather?
The Beaufort Scale itself cannot predict future weather. It is a tool for describing current wind conditions based on observation. However, a rapid increase in the Beaufort force over a short period can be an important indicator of an approaching storm or a significant change in the weather system. Meteorologists use this data alongside other information like barometric pressure and cloud formations for accurate forecasting.
