Alderney Race
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
[edit]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
[edit]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
[edit]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
[edit]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]
References
[edit]- ^ Raz Blanchard Website Wikimanche.
- ^ Courants de marée SHOM ouvrage ISBN 2-11-088197-6
- ^ "West Normandy Marine Energy". Archived from the original on 2014-10-06. Retrieved 2014-09-26.
- ^ Tidal power Archived 2015-09-24 at the Wayback Machine developpement-durable.gouv.fr, March 2013. see page 46.
See also
[edit]- La Hague – Administrative division in Normandy, France
- English Channel – Arm of the Atlantic Ocean that separates southern England from northern France