Both The north and south Cornish coasts are on flood alert as huge waves combined with high tides are expected on Sunday and into Monday.
The Environment Agency is warning that strong winds, tidal surge and large waves are expected to cause flooding at exposed locations.
Gusts of up to 40mph and a swell in excess of 30 feet are forecast.
Locations with damage to defences, buildings and structures will be especially vulnerable to the predicted large waves. These locations include: Bude, Newquay, Perranporth, Portreath and St Ives.
A spokesman said: "Strong winds are forecast for the period and large waves are expected to build during Sunday and through Monday. Conditions in exposed locations will be dangerous so please remain a safe distance from coastal frontages.
"Conditions will usually apply two to four hours either side of high tide."
The flood warning is also in place for the south Cornish coast, including Penzance, Newlyn Green, Marazion, Longrock, Porthleven, St Mawes, Pentewan, Looe, Seaton, Kingsands, Cawsands and Plymouth.