Each year, one of Britain's most famed natural phenomena occurs on the river Severn. The Severn Bore it is a large tidal wave that works its way up the Severn Estuary,over a distance of 25 miles between Awre and Gloucester.
Its caused by a rise in tide in a funnel-shaped river. In brief, as the tide from the Atlantic enters the Bristol Channel the volume of water is filtered into a narrow channel which increases the height of the water by anything up to 15 metres. Its also no mean wave and has an average speed of 16km per hour and can be up to two metres in height.
It even has it own club, the Severn Bore's Rising club which can be contacted at www.thelongwave.com/buzz/boreriderscom.html or check out the extensive pictures at www.severnbore.co.uk.