A number of caravans were left teetering on the edge of a cliff at Porthkerry, in Barry, after a sudden rock fall overnight.
There are more than 300 caravans on the leisure park, 15 had to be moved inland after being left perilously close to the cliff edge after the landslide.
Coastguards confirmed they received a call to attend Porthkerry Leisure Park at around 22:00GMT on Monday 31 October.
A local lifeboat crew were deployed but found that nobody was injured or in imminent danger.
A spokesperson for the Vale of Glamorgan council confirmed they were investigating the incident and working to make the area secure.
Miles Punter, head of visible services at the Vale of Glamorgan Council said:
“Any significant rock fall or incident of coastal erosion is clearly a matter of concern and we are currently investigating this particular incident.
“I would however point out that while the council has a role in monitoring the coastline in its area, the responsiblity for protecting private land and property along the coastline lies with the relevant land or property owners.
“The council has adopted a ‘Shoreline Management’ plan for this section of the coast which suggests that any repairs to cliffs or the introduction of any built sea defences would be inappropriate, recommending instead, ‘no active intervention’.
“Our officers will however assess the current site risks from this recent occurrence and advise the landowners of any remedial works that may be necessary, including those that my be required to protect users of the beach.”
The area around Porthkerry is used by Cardiff University’s Earth and Ocean sciences department to train their Applied Environmental Geology masters students
Responding to news of the rockfall course director Dr Peter Brabham said that the high tidal range along the south Wales coast and the alternating soft and hard nature of rock puts the area around Porthkerry at risk of erosion and rockfall which can occur with little notice.
He added however that little movement has been recorded in the area since World War II as the cliff base is protected by a pebble beach:
“The cliff is largely protected at its base by the famous pebble beach at Cold Knap which absorbs the wave energy slowing down erosion and rockfalls.
“The area has the second highest tidal range in the World so tidal erosion is a big problem along the South Wales coast.
“Over the past 10,000 years since the last Ice age rising sea level has eroded the soft shales away at the base of the cliff causing regular rock falls.
“Probably since the huge storms of the 16th and 17th century the Cold Knap pebble beach that was developed has protected the area from major erosion.
” Romans used to sail boats into Porthkerry thats not possible today because of the beach pebbles.
“All along the coast from Barry to Southerndown which has similar geology suffers regular rock falls.
“The alternating hard and soft nature of the rocks results in rapid failures with possibly only some evidence of cracks appearing a few days beforehand on the top of the cliff.
“1945 German Luftwaffe air photography of Barry docks available on Google Earth shows however that the cliff has not retreated significantly over the past 60 years.
“As geologists we only go near these cliffs wearing hard hats.
“Its very important to employ professional geologists who understand rock failures to inspect coastal sites.”
VIDEO: Dr. Peter Brabham speaks to Jane Solomons about erosion around Porthkerry