The Roaring Forties are strong westerly winds that occur in the Southern Hemisphere, generally between the

latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...

s of 40° and 50° south. The strong

east East is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fact that ea ...

ward air currents are caused by the combination of warm air being displaced upward from the

Equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

towards the

South Pole The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is the point in the Southern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True South Pole to distinguish ...

Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in progra ...

, and the scarcity of

landmass A landmass, or land mass, is a large region or area of land that is in one piece and not noticeably broken up by oceans. The term is often used to refer to lands surrounded by an ocean or sea, such as a continent or a large island. In the fiel ...

es to serve as windbreaks at those latitudes. The Roaring Forties were a major aid to ships sailing the Brouwer Route from

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

to the

East Indies The East Indies (or simply the Indies) is a term used in historical narratives of the Age of Discovery. The ''Indies'' broadly referred to various lands in Eastern world, the East or the Eastern Hemisphere, particularly the islands and mainl ...

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

during the

Age of Sail The Age of Sail is a period in European history that lasted at the latest from the mid-16th (or mid-15th) to the mid-19th centuries, in which the dominance of sailing ships in global trade and warfare culminated, particularly marked by the int ...

, and in modern times are favoured by

yachtsmen Yachting is recreational boating activities using medium/large-sized boats or small ships collectively called yachts. Yachting is distinguished from other forms of boating mainly by the priority focus on comfort and luxury, the dependence on mar ...

on round-the-world voyages and competitions. The boundaries of the Roaring Forties are not consistent: the wind-stream shifts north or south depending on the season. The strong and continuous winds in the Roaring Forties make this zone advantageous for

wind power Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity ge ...

in places such as New Zealand and Tasmania. Similar but even stronger conditions that occur at more southerly latitudes are called the Furious Fifties and the Shrieking or Screaming Sixties.

Dynamics

Hot air rises at the Equator and is pushed towards the poles by cooler air travelling towards the Equator (an atmospheric circulation feature known as the

Hadley Cell The Hadley cell, also known as the Hadley circulation, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward near the tropopause at a height of above the Earth's surface, cooling and des ...

). At about 30°S, the outward-travelling air sinks to lower altitudes, and continues toward the poles closer to the ground (the

Ferrel Cell Atmospheric circulation is the large-scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth. The Earth's atmospheric circulation varies from year to year, but ...

), then rises up again from about 60°S as the air joins the Polar vortex. This travel in the 30°–60°S zone combines with the rotation of the earth to move the air currents from west to east, creating westerly winds. The large tracts of open ocean south of 40°S are interrupted only by

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, and the southern part of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. These relatively small obstructions, which are themselves bordered by large tracts of open water along their southern shores, allow high wind speeds to develop – much higher than near 40°N, where the large continents of

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

and

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

impede the flow of circum-planetary westerly winds. The latitude ranges for the ''Roaring Forties'' and similar winds are not consistent: all shift towards the South Pole in the southern summer, and towards the Equator in the southern winter.

Wellington Wellington is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the third-largest city in New Zealand (second largest in the North Island ...

, the capital of New Zealand, is known as "Windy Welly" because it is one of the few cities situated in these gusty latitudes.

Use for sailing

During the

, ships travelling from Europe to the

would sail down the west coast of Africa and round the

Cape of Good Hope The Cape of Good Hope ( ) is a rocky headland on the Atlantic Ocean, Atlantic coast of the Cape Peninsula in South Africa. A List of common misconceptions#Geography, common misconception is that the Cape of Good Hope is the southern tip of Afri ...

to use the Roaring Forties to speed their passage across the Indian Ocean, then on the return leg, continue eastwards across the Pacific Ocean and south of

Cape Horn Cape Horn (, ) is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island. Although not the most southerly point of South America (which is Águila Islet), Cape Horn marks the nor ...

before sailing up the east coast of the

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

to home. It was first used by Dutch explorer

Hendrik Brouwer Hendrik Brouwer (; 1581 – 7 August 1643) was a Dutch explorer and governor of the Dutch East Indies. East Indies Brouwer is thought to first have sailed to the Dutch East Indies for the Dutch East India Company in 1606. In 1610, he lef ...

in his Brouwer Route, discovered in 1611, which effectively halved the duration of the trip from Europe to

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

. "To run the easting down" was the phrase used to describe the fast passages achieved in the Roaring Forties. Modern round-the-world sailors also take advantage of the Roaring Forties to speed travel times, in particular those involved in record attempts or races. An old sailor's expression goes, "below 40 degrees south, there is no law; below 50 degrees, there is no God."

Impact of pollution

The peak band of winds has moved approximately 2.5 degrees south in the late 20th century, from a combination of human-induced

ozone depletion Ozone depletion consists of two related events observed since the late 1970s: a lowered total amount of ozone in Earth, Earth's upper atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar ...

and

greenhouse gas Greenhouse gases (GHGs) are the gases in the atmosphere that raise the surface temperature of planets such as the Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. T ...

emissions. This has caused faster warming across much of southern Australia (especially in winter) and less rainfall in Western Australia.

Popular culture

The story ''Easting Down'' by '' Shalimar'' describes the events that befall a

steamship A steamship, often referred to as a steamer, is a type of steam-powered vessel, typically ocean-faring and seaworthy, that is propelled by one or more steam engines that typically move (turn) propellers or paddlewheels. The first steamships ...

unwisely venturing into the Roaring Forties to achieve a faster passage. In 1982, French filmmaker Christian de Chalonge directed '' The Roaring Forties'', a drama movie inspired by the death of Donald Crowhurst, a British sailor who perished in the 1969 Sunday Times Golden Globe Race.

References

External links

* {{cite web , title=Clipper ships in heavy weather , publisher=

University of Maryland, Baltimore County The University of Maryland, Baltimore County (UMBC) is a Public university, public research university in Catonsville, Maryland named after Baltimore County, Maryland, Baltimore County. It had a fall 2022 enrollment of 13,991 students, 61 un ...