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What are the Roaring Forties?

Sailors call the latitudes between 40 and 50 degrees south of the equator the Roaring Forties.

During the Age of Sail (circa 15th to 19th centuries), these strong prevailing winds propelled ships across the Pacific, often at breakneck speed. Nevertheless, sailing west into heavy seas and strong headwinds could take weeks, especially around Cape Horn at the southern tip of South America, making it one of the most treacherous sailing passages in the world.

Gregory Crouch, in his book Enduring Patagonia, describes them with the eyes of a mountaineer, and this is what he says:

"To court these summits is to graft fear to your heart, for all is not idyllic beauty among the great peaks of Patagonia. They stand squarely athwart what sailors refer to as the "roaring forties" and "furious fifties"- that region of the Southern Hemisphere between 40° and 60° south latitude known for ferocious wind and storm. The violent weather spawned over the Patagonia Andes with gale-force wind, roaring cloud, and stinging snow. Buried like a rapier deep into the heart of the southern ocean, Patagonia is a land trapped between angry torrents of sea and sky."

The Roaring Forties take shape as warm air near the equator rises and moves toward the poles. This is the result of nature trying to reduce the temperature difference between the equator and at the poles created by uneven heating from the sun.

This process sets up global circulation cells, which are mainly responsible for global-scale wind patterns. The air descends back to Earth's surface at about 30 degrees' latitude north and south. Air is then deflected toward the poles, and the Earth's rotation deflects them to the west, causing strong westerly and prevailing winds at approximately 40 degrees. These winds are the Roaring Forties.

The Roaring Forties in the Northern Hemisphere don't pack the same punch that they do in the Southern Hemisphere. This is because the large land masses of North America, Europe, and Asia obstruct the airstream, whereas, in the southern hemisphere, there is less land to break the wind. This is especially true south of Australia and Africa, where Patagonia is the only obstacle facing these winds in their race around the Globe.

While the Roaring Forties may be fierce, 10 degrees south there are even stronger gale-force winds called the Furious Fifties. And 10 degrees south of the Furious Fifties lie the Shrieking Sixties! We can thank the brave sailors of yore for these wildly descriptive terms.

The Uncharted team knows well about those winds. In several expeditions, we have felt humbled by this vivid display of nature's power, which sometimes doesn't let us walk and hardly lets us breathe.

Have you felt the fury of the Patagonian winds?

Source: NOAA

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