What is causing the extreme tides along the coast?

Sunset at low tide on Brighton seafront. To the left is the sea and the West Pier, a silhouette in front of a blue and orange sky. There are two people walking on the rightImage source, Zac Sherratt/BBC
Image caption,

People were treated to sand beneath their feet during the low tide - a welcome break from the pebbles on Brighton seafront

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Hundreds of people have been gathering on the shores of Sussex to catch a glimpse of a combination of spectacular sunsets and unusually low tides.

Current spring tides meant the sea level in Brighton was so low on Thursday that people were able to walk out to the West Pier – and it is set to be even lower on Friday evening.

The tides occur twice a month, but what we are seeing now is a spring tide occurring during the September equinox.

David Mearns, an oceanographer from Midhurst in West Sussex, said: “Spring tides occur during full moons, when the Moon is between the Earth and the Sun, with the added gravitational effect making the tides bigger.

Image source, Zac Sherratt/BBC
Image caption,

The tide allowed people to get up close to the West Pier

“The September equinox is when the Moon is further from the equator – and thus closer to our northern position.

“Anybody who has looked out at the Moon recently will know that the Moon is very close to us at this time.

“So in this case, it makes the normal spring tide the greatest - in terms of a low and a high – during the year. The tide is an effect of that closeness.”

Image source, Zac Sherratt/BBC
Image caption,

The RNLI has reminded people to stay aware of their surroundings at low tide

Some experts even believe that this could be the lowest we will ever see the water level.

Coastal engineer Hamish Hall told BBC South West: "It's probably another 10 years before we see this type of low tide again.

"With sea level rise projections we may never see this predicted low tide again."

The Met Office believes sea levels are rising by 3-5.2mm (0.1-0.2in) a year.

The RNLI has issued a reminder for people on the coast tonight.

Volunteer water safety officer at Brighton RNLI Vicki Linton-Crook said: "We hope everyone enjoys the beautiful views expected tonight but please do remember to stay safe.

"The sea is unpredictable and can change quickly, so check the direction of the tide before you go to the sea and stay aware of your surroundings at all times."

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