What we know about the conditions around Bournemouth Pier during tragic beach incident

Tragedy struck a packed Bournemouth beach yesterday as two youngsters died after being pulled from the sea.

Eight other people were recovered from the water after getting into difficulty off the main pier as thousands of sunseekers enjoyed the sunny half-term weather.

They were treated by paramedics for non-life-threatening injuries.

An investigation into the circumstances surrounding the incident has been launched by Dorset Police, the Marine Accident Investigation Branch and the Maritime and Coastguard Agency.

Dorset Police said the two deceased - a 17-year-old boy and a 12-year-old girl - sustained “critical injuries” and that, following enquiries, a 40-year-old man, who had been on the water at the time , has been arrested on suspicion of manslaughter.

It is believed the man was on a jet ski.

What we know about the area

Jet skis and other watercraft operating in the Bournemouth and Poole areas must follow specific rules between April and October.

Unconfirmed reports say those involved in the incident had jumped off the pier - which is some 1,000ft (304m) long - and were pulled further out by a riptide.

Bournemouth, a popular seaside town on England’s south coast, is popular with locals and tourists during the summer months.

Average temperatures in and around the pier area are 12.4C for the month of June and can exceed 16 in September, according to the surf-forecast website.

The website says the area tends to receive a mix of “groundswells” and “windswells”, with surfers warned to “watch out for rips and crowds.

Bournemouth Pier, like all outcrops in the ocean such as groins, headlands or sandbars, presents danger for swimmers due to riptides, or rip currents.

Rips, as they are commonly known, occur when water that has been pushed towards land by the sea, is tracking back out, creating a channel of water which pulls back out to sea.

Rips are often harmless, and swimmers will barely notice them, but typically around large headlands or piers, they can be powerful and drag unwitting swimmers and surfers out to sea, particularly if there is a large swell running.

Piers and cliffs also present a hazard in summer because of the popular pursuit of ‘tombstoning’, or cliff-jumping, where thrill-seekers throw themselves into the sea off of the side of these outcrops.

Frequently people unfamiliar with conditions are hurt, or even killed, due to shallow water, hitting people in the ocean below, or landing in a dangerous position.

The sea conditions in Bournemouth when the incident happened appeared to be calm, with very little swell running. The water temperature was 15 degrees, meaning a wetsuit is required to swim comfortably.

The tides at Bournemouth see two highs and two lows in a 24-hour period. Like the rest of the UK, the tidal range is large, exposing large swathes of sand at low tide.

Low tide on 31 May was at 1:44pm and it was a 1m tide, while high tide was at 7:35pm and was 1.89m - making it a large tide.

This means the incident happened at mid-tide when the water would have been pushing shorewards.

Tobias Ellwood, the MP for East Bournemouth and chair of the defence committee, told Sky News that the pier was “involved” in the tragedy.

The local council will review its protocols in relation to what can be conducted on the pier, he added.