- The Severn Bore is a surge wave on the River Severn that is produced by the incoming tide.
- It occurs on 130 days, and appears twice on those days, coinciding with days after the full and new moons.
Description
- The highest Bores occur at the Equinoxes, but large ones occur 1-3 days after the new and full moons.
- The wave starts as a 700 mile (1,100km) wide tidal wave in the Atlantic and as it moves into the Bristol Channel and River Severn estuary its width decreases but its height increases, and it now travels in a series of 3 or more waves.
- The Bore will travel upriver at a height of 2 feet (0.6m) as far as Gloucester and may reach Tewksbury before dissipating over the weirs.
- The Bore travels at a speed of up to 13 mph (21kph) and attracts surfers and canoeists to ride its leading edge.
- The water level of the river continues to rise for up to one and a half hours after the Bore has passed.
- Every year the timetables are published with Bore dates, timings along the route and the heights.
Severn Bore at 11.19 Over Bridge, Gloucester on 02/09/23.