The Alderney Race is a strait that runs between Alderney and Cap de la Hague, a cape at the northwestern tip of the Cotentin Peninsula in Normandy. A strong current runs through the race north of the Passage de la Déroute, a treacherous passage separating the Cotentin from the Channel Islands. The current is intermittent, varying with the tide, and can run up to about 12 knots (22 km/h; 14 mph)[citation needed] during equinoctial tides. The French call it Raz Blanchard.[1] In Norman French it is called L'Raz.

Location

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Passage de la Déroute.

The Alderney Race is 8 nautical miles (15 km; 9.2 mi) across and located roughly between Alderney, in the Bailiwick of Guernsey, and La Hague, France. It constitutes the northeastern limit of the Gulf of Saint-Malo.

Sea conditions

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When the wind and the race current flow in opposite directions, the sea becomes particularly chaotic: wave heights can reach 4 metres (13 ft) and have wavelengths smaller than 50 metres (164 ft). The waves break with violence, thus making shipping conditions particularly dangerous.[2] On the contrary, when the wind and the stream flow in the same direction, the sea becomes calm, provided that the tidal coefficient is not too great.

The uneven seabed – both Alderney and La Hague lie in the Armorican Massif – makes the situation more complicated. Bad weather can produce abundant wind-blown foam, making visibility poor. During good weather, opposing wind and currents can cause breaking waves, especially at Banc de la Schôle and at Longis Bay in Alderney.

Hydrology

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The power of the current comes from the narrowness of the strait and from the fact that there is a 2-metre (6 ft 7 in) tidal height difference between Carteret and La Hague as well as between la Hague and Cherbourg.

Tidal power

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Because of the enormous potential it sees in tidal power, the French government plans to use tidal turbines to tap the energy of the Race.[3][4]

Alderney and the Alderney Race seen from Auderville in France.

References

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  1. ^ Raz Blanchard Website Wikimanche.
  2. ^ Courants de marée SHOM ouvrage ISBN 2-11-088197-6
  3. ^ "West Normandy Marine Energy". Archived from the original on 2014-10-06. Retrieved 2014-09-26.
  4. ^ Tidal power Archived 2015-09-24 at the Wayback Machine developpement-durable.gouv.fr, March 2013. see page 46.

See also

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  • La Hague – Administrative division in Normandy, France
  • English Channel – Arm of the Atlantic Ocean that separates southern England from northern France

49°43′N 2°04′W / 49.72°N 2.07°W / 49.72; -2.07