A Jurassic Coast cliff collapse last week was the second landslide of its kind in the area in a fortnight, likely caused by the extreme heat.

The rockfall at Sidmouth Beach in Devon, saw parts of the cliff face continue to fall for hours afterwards. It followed another landslide along the same coastline during July’s heatwave.

Due to the risk, Dorset Council already put a warning in place appealing to beachgoers to take extra precautions.

Catherine Pennington, Landslide specialist at the British Geological Survey, said: “Landslides can occur on our dynamic coast at any time and the science research to fully understand the link between rockfalls and temperature fluctuations is still ongoing.

“What we do know is that cracks can form or widen during these changes in temperature. In general, cracks related to instability can be very difficult to see from the cliff top, as can unsupported, overhanging rocks so, as well as staying well away from the cliffs on the beach, it is also important to stay away from cliff edges at the top.”

With the prolonged high temperatures, and a Met Office weather warning in place, Dorset Council has warned of an increased risk of rock falls along Dorset’s World Heritage coastline.

According to the council’s website, this is because heat causes rocks to expand and, particularly during temperature fluctuations, any pre-existing cracks can widen, and new cracks can also form. This makes cliffs potentially more unstable and rockfalls more likely to happen.

While Dorset and East Devon’s Jurassic Coast is famous for eroding rock exposing fossils, the rockfalls can be devastating if people are beneath them at the time of the fall.

Councillor Ray Bryan, Portfolio Holder for Highways, Travel and Environment, said: “Rockfalls are entirely unpredictable and can happen at any time, but we do know which conditions make them more likely, and prolonged hot and dry spells are one of them.

“We would encourage anyone thinking of visiting the Dorset coast during this heatwave to stay away from the base of cliffs, and if you are walking along the coast paths, keep well away from the edges. Never ignore a warning sign – they are there for your safety.

“It is easy to enjoy the spectacular and fascinating Jurassic Coast without putting yourself or others at risk.”

Dorset’s coastline has a number of areas with an increased potential for rockfalls, particularly on the cliffs around Seatown, Eype, Burton Bradstock, West Cliff, East Cliff, Mupe Bay, Lulworth and Swanage.