The Severn bore is not an alcoholic local who sends you to sleep with lots of uninteresting stories. It is a tidal wave.
The Severn has the second highest tidal range in the world, more than 14.5 metres and when this tide suddenly increases it is restricted by hard rocked river banks at Sharpness, where there are also ledges in the river bed. This holds up the water and stops it flowing forward, the waters pile up and the bore is formed.
It builds speed and height as the river gets shallower and by the time it reaches Minsterworth it can be travelling at 16kmph and can be 2 metres tall. The largest bore was 9 feet tall. In all the bore travels 21 miles between Awre and Gloucester and they usually occur 1-3 days after a new full moon.
The best places to watch the Bore are at Minsterworth, Framilode and Stonebench.
A comical sight is the surfers who regularly try to ride the bore up the river. The bore is very dangerous and high tides can become a problem leaving viewers stranded and in need of rescue.