Severn Bore and Trent Aegir

Learn more about these naturally occurring tidal waves, and find out when and where you can view them.

Download the complete guide to the Severn Bore and Trent Aegir

If you would like us to send you a hard copy of this guide, please phone us on 08708 506 506.

The Severn Bore

  • The Severn Bore can reach two metres in height.
  • Its average speed is 16km per hour.
  • The Severn Estuary experiences the second highest tide anywhere in the world.
  • The difference between the lowest and highest tide in any one day can be more than 14.5 metres.
  • Because of the weirs, there is no Severn Bore upstream of Gloucester.

  • Severn Bore predictions 2010 (PDF, 64KB)

The Trent Aegir

  • The Trent Aegir is named after the god of the seashore or ocean in Norse mythology - and like the Scandinavian sailors in the myths, river people would fear the coming of the aegir as it is very unpredicatable and would sometimes destroy ships.

  • It usually appears during high spring tides, but as with the Severn Bore, its size can be affected by floods and rises in water levels.

  • Trent Aegir predictions 2010 (PDF, 70KB)

The size of a bore or aegir can be affected by winds or high freshwater levels. High freshwater levels reduce its height and delay its time of arrival. An following wind can increase its height and advance the time it arrives.