The Environment Agency has issued a flood warning for the Barbican, Sutton Harbour and parts of Plymouth waterfront as high tides and gale force winds combine.
Tidal waters flooded parts of Plymouth this morning after warnings high tides and gale-force winds would lead to problems.
There are warnings there could be more flooding for the four hours around high tide at 8pm tonight.
Twitter user baldyo7 uploaded a picture of parts of the city's waterfront being flooded by a high tide at 8am.
This morning's high tide was 7.31am in Plymouth with warning of flooding two hours either side of the surge.
High tide is set to raise the water off Plymouth by 2.6 meters with the surge adding another 37 centimetres.
A spokesman said: "Very significant wave and spray overtopping can be expected at exposed locations, making conditions particularly dangerous. Extreme caution should be exercised."
Wind force is seven. There were a number of properties, including shops, flooded in Looe this morning and the Liskeard-Looe railway line was closed.
The harbour master in Looe, in south Cornwall, said the flooding to properties close to the sea was the worst he had seen in the seven years he had been there.
Jeff Penhaligon said the water had subsided after Wednesday morning’s high tide but the village was now preparing itself for the next one, at about 8pm on Wednesday evening.
He said: “I’ve been back here for seven years and it’s the worst I’ve seen. We flood quite regularly with the tides but not normally as bad as this.
“It’s difficult to see exactly who’s been affected but I think some of businesses and restaurants near the harbour. It all depends whether people were able to get their storm boards up.”
Mr Penhaligon said no fishing boats had gone out on Wednesday. “You wouldn’t want to go out in this in a small boat,” he said.
The Environment Agency is closely monitoring the Devon and Cornwall coast today ahead of high spring tides later this afternoon and urging people to remain vigilant and alert for possible tidal flooding.
The high tides could combine with gusts of wind causing flood surges in some parts of Devon, Dorset and Cornwall between 6pm and 8pm today (Wednesday, 17 October).
Sixteen flood warnings and 18 flood alerts have been issued for parts of Devon, Cornwall and Dorset, where the high tides and storm surges could also see flooding of coastal areas.
High tides are expected in Cornwall and Devon between 6pm and 8pm. Strong winds and high tides also bring the potential for waves and spray to come over the top of sea defences at coastal locations. These are similar conditions to those which resulted in some localised flooding in Devon and Cornwall following high tides this morning.
Environment Agency staff have worked through the night monitoring high tide levels, closing sea defences, checking pumping stations and making sure that professional partners are aware of the situation and will continue to do so throughout the rest of the week.
‘With the high spring tides, and anticipated wind surges, our teams are working hard to ensure we are prepared and are working with our professional partners to make sure the public are aware of the risk. We are receiving regular weather updates from the Met Office, continuously monitoring both tidal conditions and river levels and have had officers out overnight checking flood defences and closing flood gates,’ said David Bunt for the Environment Agency.
‘People should be aware that there could be a lot of water in coastal areas, so avoid trying to drive or walk through any flood water and be sensible when out and about, particularly around the coast. Now is a good time for anyone who lives in an area vulnerable to flooding to think about the precautions they can take to protect their properties.’
Flood gates have been closed at Sutton Harbour.
The west and south coast of Wales and the coasts of Devon, Cornwall and Somerset are likely to experience gusts of up to 60mph, forecasters said.
The Environment Agency said strong westerly winds would cause stormy seas which, combined with some of the highest tides of the year, would lead to high sea levels and spray coming over sea walls.
Low-lying coastal roads, farmland and isolated houses could be vulnerable to flooding, but the agency is also warning of the possibility of more significant problems.
There are currently 25 flood warnings in place, mostly for coastal areas in the South West and Wales, with one also in the North East, and high tides are likely to lead to more warnings being issued.
Gemma Plumb, a forecaster with MeteoGroup, the weather division of the Press Association, said there would be gusts of 50 to 55mph throughout the day along the south west Wales coast and would reach up to 60mph in places, while in Devon and Cornwall they would be between 40 and 55mph.
The Met Office said winds were expected to increase to “gale or severe gale force” on exposed parts of the coast, which could lead to localised disruption to transport.
The Environment Agency said its teams had been out checking flood defences and closing tidal gates ahead of the high tides, and warned people to be careful driving or walking along the coast over the next few days.
People should be particularly careful on exposed areas, where there is a risk of being swept away by waves or being hit by debris thrown up by waves, the agency added.