Coastguards have warned “phenomenal” waves are expected to pound the Cornish coastline later today.
Richard Williams, from Falmouth Coastguard, said the inshore forecast showed they are expecting waves of more than 45ft (14 metres), classing the sea state as phenomenal.
The waves are predicted for 12 miles (19km) offshore, and Mr Williams said: “To be that sort of sea state inshore is unusual particularly in this part of the world.”
Mr William urged people to stay away from the coast.
He said: “Be aware of the conditions out there. Do not go wave watching and if you are by the coast be aware that the sea may be much rougher than usual.
“It is really important that people understand not to take any chances as it only takes a small amount of water to wash you off your feet.”
The Met Office has issued an amber warning for high winds for gusts of up to 60 to 70 mph along the coast and 80 mph in some isolated areas.
The chief forecaster said: “These winds will also whip up large waves over the eastern Atlantic which will affect south-west facing coasts during Saturday. The very strong winds are expected to last into Sunday morning for many parts.”
Areas most at risk of flooding are Mullion, Newlyn, Looe, Porthleven, Kingsand and Cawsand.
Cornwall Council provided a coordinated response throughout last night to unfolding events from County Hall through Silver Command and will continue to do so today.