Severn bore
Encyclopedia
Tidal bore
A tidal bore is a tidal phenomenon in which the leading edge of the incoming tide forms a wave of water that travel up a river or narrow bay against the direction of the river or bay's current...
seen on the tidal reaches of the River Severn
River Severn
The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...
in England. It forms somewhat upstream of Sharpness
Sharpness
Sharpness is an English port in Gloucestershire, one of the most inland in Britain, and eighth largest in the South West. It is on the River Severn at , at a point where the tidal range, though less than at Avonmouth downstream , is still large .The village of Sharpness is pronounced with the...
, and can be seen as far upstream as Maisemore
Maisemore
Maisemore is a village and civil parish in Gloucestershire, England. It lies on the A417 road 2.5 miles northwest of Gloucester, on the west bank of the River Severn. In the 2001 census the parish had a population of 488. There is a church, dedicated to St Giles.Maisemore Bridge connects the...
.
Formation
The Severn EstuarySevern Estuary
The Severn Estuary is the estuary of the River Severn, the longest river in Great Britain. Its high tidal range means it has been at the centre of discussions in the UK regarding renewable energy.-Geography:...
, which empties into the Bristol Channel
Bristol Channel
The Bristol Channel is a major inlet in the island of Great Britain, separating South Wales from Devon and Somerset in South West England. It extends from the lower estuary of the River Severn to the North Atlantic Ocean...
, has the second largest tidal range
Tidal range
The tidal range is the vertical difference between the high tide and the succeeding low tide. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth...
in the world — about 49 feet (15 m), exceeded only by the Bay of Fundy
Bay of Fundy
The Bay of Fundy is a bay on the Atlantic coast of North America, on the northeast end of the Gulf of Maine between the Canadian provinces of New Brunswick and Nova Scotia, with a small portion touching the U.S. state of Maine...
. During the highest tides rising water is funneled up the estuary into a wave that travels upstream against the river current at a speed of 8 to 13 miles per hour. The largest bores occur in spring but smaller ones can be seen throughout the year. The Environment Agency
Environment Agency
The Environment Agency is a British non-departmental public body of the Department for Environment, Food and Rural Affairs and an Assembly Government Sponsored Body of the Welsh Assembly Government that serves England and Wales.-Purpose:...
publishes timetables and predictions of bore heights on its website. Being the onset of the flood tide it is accompanied by a rapid rise in water level which continues for about one and a half hours after the bore has passed. The Severn bore is not a self-reinforcing solitary wave or soliton
Soliton
In mathematics and physics, a soliton is a self-reinforcing solitary wave that maintains its shape while it travels at constant speed. Solitons are caused by a cancellation of nonlinear and dispersive effects in the medium...
but rather a shock wave which is formed because the wave is travelling faster than the wave speed in water above the Bore (see tidal bore
Tidal bore
A tidal bore is a tidal phenomenon in which the leading edge of the incoming tide forms a wave of water that travel up a river or narrow bay against the direction of the river or bay's current...
for more details).
The largest recorded bore was on 15 October 1966, when it reached a height of 9.2 feet (2.8 m).
Viewpoints
The Bore is best seen at Stonebench, near ElmoreElmore, Gloucestershire
For other places with the same name, see Elmore.Elmore is a village and civil parish, located in the Stroud district of Gloucestershire, England...
, on the east bank, or at Minsterworth
Minsterworth
Minsterworth is a village in Gloucestershire, UK. It lies on the border of Gloucester, on the north bank of the River Severn and on the A48 road between Gloucester and Chepstow, at...
on the west bank. It can also be seen at Over Bridge
Over Bridge
Over Bridge is a single span stone arch bridge spanning the canalised West Channel of the River Severn near Gloucester. It links Over to Alney Island....
.
As a natural spectacle, in some respects, the bore is best viewed (and heard) at night when there is less chance of powerboats etc. on it, and/or just in front of it. The engine noise masks the sound of the wave and their wake(s) diminish the spectacle of a single wave rapidly advancing up a smooth river. To a certain extent it can still be seen in the dark and many spectators have powerful torches anyway.
Surfing
River surfingRiver surfing
River surfing is the sport of surfing either standing waves or tidal bores in rivers. Claims for its origins include a 1955 ride of 1.5 miles along the tidal bore of the River Severn...
enthusiasts attempt to surf along on the wave, which can be 2 metres (7 ft) high. The river was first surfed by WWII veteran Jack Churchill
Jack Churchill
Lieutenant Colonel John Malcolm Thorpe Fleming "Jack" Churchill, DSO & Bar, MC & Bar , nicknamed "Fighting Jack Churchill" and "Mad Jack", was a British soldier who fought throughout World War II armed with a longbow, arrows and a claymore...
, a military cross awardee renowned both for carrying a claymore
Claymore
The term claymore refers to the Scottish variant of the late medieval longsword, two-handed swords with a cross hilt, of which the guards were in use during the 15th and 16th centuries.-Terminology:...
, and for being the only Allied soldier to kill an enemy with a longbow during the war. He became a surfing enthusiast in his later life and rode the bore on a board he designed himself.
In March 2006, Steve King, a railway engineer from Gloucestershire
Gloucestershire
Gloucestershire is a county in South West England. The county comprises part of the Cotswold Hills, part of the flat fertile valley of the River Severn, and the entire Forest of Dean....
, attempted to set a record for the longest-ever surf. However, the exact distance of the ride was never verified and the record was later rejected by both the British Surfing Association and Guinness World Records
Guinness World Records
Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...
.
In September 2005, several hundred surfers gathered in Newnham on Severn
Newnham on Severn
Newnham on Severn is a village in west Gloucestershire, England. It lies near the Royal Forest of Dean, on the west bank of the River Severn, approximately 10 miles south-west of Gloucester and three miles southeast of Cinderford, at . It is on the A48 road between Gloucester and Chepstow,...
to celebrate 50 years since the first recorded attempt at surfing the Severn bore and to view the première of Longwave by Donny Wright, a historical film documenting the evolution of the sport since its inception in 1955.
The Gloucester Harbour Trustees
Gloucester Harbour Trustees
The Gloucester Harbour Trustees are the Competent Harbour Authority for the tidal part of the River Severn from the Gloucester weirs down to just below the Second Severn Crossing and on the River Wye up to its tidal limit .The Trustees have responsibilities for navigational safety in that part of...
, as competent harbour authority for this part of the river, have issued safety guidance for surfers, canoeists,
small craft and river bank users in relation to the bore.
External links
- The Severn Bore Page
- Severn Bore, Surfing Spot South of Minsterworth on BlooSeeBlooseeBlooSee is a social network and an ocean web mapping site where sailors, divers, surfers and other sea lovers geotag and share information and knowledge about the oceans. BlooSee is built in Python and uses the Google Maps API.BlooSee is owned by BlooSee, Inc...
Exact location and satellite map - Severn Bore, Surfing Spot at Over Bridge on BlooSeeBlooseeBlooSee is a social network and an ocean web mapping site where sailors, divers, surfers and other sea lovers geotag and share information and knowledge about the oceans. BlooSee is built in Python and uses the Google Maps API.BlooSee is owned by BlooSee, Inc...
Exact location and satellite map - Severn Bore viewing sites (Environment Agency)