Severn bore

Severn boating

The Severn Bore

Many times a year, the high Spring tide forms a wave that surges up the River Severn as a wall of water.

As the bore passes, the depth of water in the river instantly rises and may flood the bank.

The flow of the river is reversed and remains so until the tide begins to ebb.

The height of the Severn bore depends on a number of factors but the most important is the tidal range.

Depending on the depth of water, the bore may be a smooth wave or have a breaking crest.

The wall of a large bore may be 2 metres high and travel at some 14 knots.

Where to see the Severn Bore

There are numerous viewing points on the river bank anywhere north of about Newnham.

The most popular sites, with easy access from roads are at Over Bridge, Minsterworth and Stonebench.

Stonebench is also within walking distance of the Sharpness canal.

If a large Severn bore is predicted there will be many hundreds of visitors.

A small bore wave surging up the River Severn. For scale note the rigid inflatable on the tidal side.

Picture taken from the bank at Stonebench where the river channel is narrow.

The bore wave is interrupted by weirs near Gloucester but the effects of the bore continue upto Tewkesbury.

small severn bore with surfers at Stonebench

Remember, as the bore passes it will often break violently along the bankside; the river level will instantly rise and will often flood the adjacent area.

Visitors should choose their viewing point with care.

Dates and Times of the Severn Bore

The best bores normally occur around high Spring tides in Feb - Mar and Aug - Oct each year.

Because they are tidal features, it is posssible to predict dates and approximate times of arrival.

Bores occur when the range of tide (the difference between Low and High Water) exceeds 12.5m at Avonmouth

Approximate times of arrival are Newnham (15 mins before HW Avonmouth), Stonebench (HW +1) and Over Bridge (HW + 1hr 20 min).

Tidal bores of the World

In places where there is a large tidal range, many rivers have a tidal bore. Alternative names, in different parts of the world, include aegir, eagre, pororoca and mascaret

The bore on the Qiantang River in China, with a height of nearly 9m, is the largest in the world.

Disclaimer: All linked sites are believed to be in the public domain. They are verified regularly but the Severn-boating page accepts no reponsibility for the nature or accuracy of information on those sites.