Holidaymakers have been urged to stay away from a "sheer cliff" of sand due to a high risk of it collapsing two months after a child narrowly escaped with their life.
Lifeguards in Crantock, near Newquay, have said there is an "increased danger" of the huge dune at the beach collapsing further, potentially trapping sun worshippers beneath it.
A 65ft-high dune collapsed on Wednesday after dry weather caused sand to shift at the popular beach, which has been eroded by surf gouging away at the base of the sand structures.
While the sand may appear light and moveable, if a large amount of it were to fall on top of a person, it would prove incredibly heavy and difficult to move.
Newquay's RNLI lead lifeguard supervisor Lewis Timson said: "Sand is extremely heavy, and in the event of the dune collapsing, there is an increased danger of becoming buried with potentially life-threatening consequences.
"Despite the important, multi-agency training we have recently undertaken to rescue someone trapped under sand, we hope we do not face any incidents of this nature.
"Our focus is on ensuring people keep away from the sand dunes at Crantock.
"With the dry weather and surf of three to four foot expected the nature of the sand dune system is predicted to shift and remain unstable for the foreseeable future and risks collapse at any time."
The warning comes two months after a a child was seen 'disappearing' into a dangerous sand cave at the beach.
The incident happened on Good Friday when members of a beach patrol saw the child entering a hole in the sand, prompting them to rush over and convince the young beach goer to come out.
The sand "collapsed with very little effort" a short while afterwards, showing how fragile the dune structures at the beach are.
The Crantock Surf Life Saving Club said it wanted to educate people to enjoy Cornwall beaches safely after the collapse, warning that "sand can suffocate" and that people should not be tempted to climb into sand caves.
Posting to Facebook, the club said: "On Good Friday one of our patrols intervened when a child was seen disappearing into this sand cave that they had burrowed into the dune cliff.
"They spoke to the child about the dangers and took action to collapse the hole safely to prevent anyone else from being tempted to climb in.
"The sand collapsed with very little effort showing just how dangerous it could have been if the sand had been dislodged by the child’s spade or someone unaware walking above.
"Collapsing sand can suffocate. This post is to help educate people to please enjoy the beach safely so please please no negative comments. Positive words and shares only please."
Signs telling punters to stay away from sand dunes and cliffs have been put up by the lifeboat charity along the stretch.
Cornwall Council issued a warning about the same dunes earlier this month, saying: "Please stay away from the base of the sand dunes at Crantock Beach. Due to the recent bad weather and spring tides, there is a risk that sand could fall from the cliffs.
"The National Trust, which owns the beach, and the RNLI are asking people to stay away from the base of the sand cliffs and not allow children to play near them. In the event of an emergency call 999 and ask for the Coastguard."
If a person is trapped beneath the sand a special technique is deployed to try and get them out, which involves a chain of people scooping sand away from the victim.
Beachgoers are urged to stay at least 50m away from the base of the dunes, and to swim between the red and yellow markers in the sea due to the current increase risk of rip currents.
