Beachgoers have been warned to stay away from the dunes at Crantock due to significant erosion.
The dunes have become “extremely” unstable after recent storms and tides.
A spokesman for Newquay RNLI Lifeguards said: “Due to significant sand dune erosion at Crantock there is a significant risk of sand collapse to anyone playing on or sitting too close to the bottom of the sand dunes which in areas has a 20 to 30ft drop.
“Please keep a safe distance from the edges and base and keep children and dogs well away.
“Call the coastguard 999 in an emergency.”