A low rumble builds in the distance, growing louder until it becomes a roar. Around the bend, a wall of water surges up the River Severn, pushing against the current with relentless force. This is the Severn Bore, a tidal wave that travels upstream for miles, drawing surfers from across the world. They paddle in the muddy water, waiting for the perfect moment to drop in and ride the wave. The bore is a phenomenon of the tides, a collision of freshwater and saltwater that creates one of the longest surf rides on the planet.
One of the most impressive displays of Mother Nature’s power can be seen along the lengths of the River Severn. The Severn Bore is considered to be the second highest tidal bore in the world as it often rises as much as 15.4 meters above the standard levels of the river.
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What Causes the Severn Bore
River bores or tidal waves are a rarity. There are only sixty known bores that occur around the world to date. Owing the formation of the Severn Bore to the shape of the river’s estuary, the tidal waves are able to form and flow down the river. The bore maintains an average roughly 14 knots as it makes its way down the river. People who visit the river banks during this even can hear the roar of the water as much as twenty two kilometers away from the head.
The unique geography of the Severn Estuary is the key to understanding this phenomenon. In Avonmouth, the River Severn estuary is nearly 9 kilometers wide. By the time that the river reaches Sharpness, the estuary is a little more than 1.4 kilometers wide. Where the river passes Minsterworth, the estuary is less than a hundred meters in width and maintains roughly the same width until it reaches Gloucester. This funnel shape causes the incoming tidal water to be compressed into an increasingly narrow channel. The water has nowhere to go but up, and the result is a wave that surges upstream against the normal flow of the river. The combination of the estuary shape, the high tidal range of the Severn (the second highest in the world), and the spring tides creates the perfect conditions for this remarkable natural event.
Best Times and Places to See the Bore
People wanting to view the power of the Severn Bore, should visit the area during the spring time. Since the bore is caused by the tides, the environment Agency is able to publish regular occurrences of the bore and its expected height. The largest bores typically occur around the spring and autumn equinoxes when the tidal range is at its greatest. The environment Agency provides a bore prediction table that lists expected times and heights for each occurrence, allowing visitors to plan their trip with precision.
One of the best viewing locations of the Severn Bore is on the eastern banks of the river in Stonebench. Some say that the best place to see the bore is from the Severn Bore Inn which is located in Minsterworth. Here there is a pub, food a car park as well as floodlights for nighttime viewing of the river bores. Some say that the best time to witness the bores is in the dark of night when you have to use a floodlight to see the water. Countless people stop at the Over Bridge which crosses the River Severn. From this viewpoint, you can watch the tidal waves as it surges directly under your feet. You can feel the force of the water rushing under the bridge as the entire ground shakes. The feeling of having witnessed the Severn Bore “Over the River” is an amazing one.
Surfing the Severn Bore
The Severn Bore is not just a spectacle for spectators. It is also a world-class surfing destination. Surfers from across the globe travel to Gloucestershire to ride this unique wave, which can be surfed for several miles as it travels upstream. The bore produces several distinct waves, with the largest reaching heights of up to two meters during spring tides. Experienced surfers have been known to ride the bore for distances exceeding ten kilometers, making it one of the longest surf rides available anywhere in the world.
The surfing season runs from around September to April, with the best conditions occurring during the highest tides. Safety is a major consideration, as the bore carries debris and the river can be cold and dangerous. Surfers are advised to use appropriate equipment and to be aware of hazards such as submerged obstacles and strong currents. Despite these risks, the thrill of riding a wave that travels against the current of a major river is an experience that draws participants back year after year. The sight of surfers silhouetted against the dawn sky as they ride the bore has become an iconic image of this extraordinary natural phenomenon.
Would you surf a wave that travels up a river? 🌊
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