Bay of Biscay

The Bay of Biscay, ( BISS-kay, -kee) also known as the Gulf of Biscay or the Gulf of Gascony, is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the northern coast of Spain, extending westward from the French border to Cape Ortegal, and along the western coast of France from Point Penmarc'h southward to the Spanish border. The average depth is 1,744 m (5,722 ft) and the greatest depth is 4,735 m (15,535 ft).

The Bay of Biscay is known in Spain as the Gulf of Biscay (Basque: Bizkaiko Golkoa; Galician: Golfo de Biscaia; Spanish: Golfo de Vizcaya). In France, it is called the Gulf of Gascony (French: Golfe de Gascogne [l.f d as.k]; Occitan: Golf de Gasconha; Breton: Pleg-mor Gwaskogn; Basque: Gaskoiniako Golkoa). In Latin, the bay was known as Sinus Cantabrorum (Cantabrian Gulf); the name Cantabrian Sea is still used locally for the southern area of the Bay of Biscay that washes over the northern coast of Spain (Cantabria). The English name comes from Biscay on the northern Spanish coast, probably standing for the western Basque districts (Biscay up to the early 19th century).

Parts of the continental shelf extend far into the bay, resulting in fairly shallow waters in many areas and thus the rough seas for which the region is known. Heavy storms occur in the bay, especially during the winter months. The Bay of Biscay is home to some of the Atlantic Ocean's fiercest weather; abnormally high waves occur there. Up until recent years it was a regular occurrence for merchant vessels to founder in Biscay storms.

The International Hydrographic Organization defines the limits of the Bay of Biscay as "a line joining Cap Ortegal (43°46′N 7°52′W) to Penmarch Point (47°48′N 4°22′W)". The southernmost portion is the Cantabrian Sea.

The main rivers that empty into the Bay of Biscay are Odet, Aven, Laïta, Scorff, Blavet, Vilaine, Loire, Lay, Sèvre Niortaise, Charente, Seudre, Garonne, Dordogne, Eyre, Adour, Nivelle, Untxin, Bidasoa, Oiartzun, Urumea, Oria, Urola, Deba, Artibai, Lea, Oka, Nervión, Agüera, Asón, Miera, Pas, Saja, Nansa, Deva, Sella, Nalón, Navia, Esva, Eo, Landro and Sor.

In late spring and early summer, a large fog triangle fills the southwestern half of the bay, extending a few kilometres inland. As winter begins, weather becomes severe. Depressions frequently enter from the west, and either move north to the British Isles or enter the Ebro Valley, dry out, and are finally reborn in the form of powerful thunderstorms as they reach the Mediterranean Sea. These depressions cause severe weather at sea and bring light but constant rain to its shores (known as orballo, sirimiri, morrina, orbayu, orpin or calabobos). Powerful windstorms may form if the pressure falls rapidly (galerna), traveling along the Gulf Stream at great speed, resembling a hurricane, and finally reaching the bay with their maximum power, such as Cyclone Klaus. The Gulf Stream enters the bay following the continental shelf's border anti-clockwise (the Rennell Current), keeping temperatures moderate all year long.

The main cities on the shores (or close to) of the Bay of Biscay are Lorient, Vannes, Saint-Nazaire, Bordeaux, Bayonne, Biarritz, Nantes, La Rochelle, San Sebastián, Bilbao, Santander, Gijón and Avilés.

Data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).