More flood warnings were issued tonight as power companies were told to make sure they are prepared for the next big storm heading for the British Isles.
Heavy rain and wind gusts of up to 60mph are expected to hit western areas tomorrow, prompting nearly 70 flood warnings.
Environment Secretary Owen Paterson, who chaired a meeting of the Government's Cobra emergencies committee, said "exceptional" weather was expected.
And he warned the energy network companies to be prepared for the latest storms following complaints it took too long to restore electricity to the thousands of homes left without power in the wake of severe weather over Christmas.
Mr Paterson's comments came as the body of a 27-year-old man, from Surrey, was found by a member of the public on Porthleven Sands beach in Cornwall this morning. He had been swept out to sea on New Year's Eve night having gone for a paddle with friends at nearby Loe Bar.
In a second tragedy on Tuesday, a woman died after being swept out to sea at the popular beauty spot Croyde Bay in north Devon. The woman, who was believed to be on holiday with her family, was rescued from the sea and airlifted to hospital before being confirmed dead by doctors.
Elsewhere, in Dorset a search was under way for a man who is believed to have fallen into the River Stour, near Iford Bridge in Christchurch yesterday.
There has been a brief respite from the most severe weather today, but heavy rain is expected in western areas of England, Wales, Scotland and Northern Ireland tomorrow as a low pressure system moves in from the Atlantic.
Areas particularly at risk include the Isles of Scilly, the north and south coasts of Devon and Cornwall, Dorset and the coastline of Wales, while the risk of flooding is made worse by the high level of ground saturation from earlier heavy rain.
There are already 12 severe flood warnings, which are issued when there is a threat to life or property, as well as more than 230 flood alerts across the country. In London, the Thames Barrier was closed to protect people and property along the river, the Environment Agency said.
Pete Fox, head of strategy at the agency, said: "We are expecting flooding along the west and south coasts of England and Wales, due to a combination of strong winds, large waves and high tides, from the early hours of Friday and into the weekend.
"Coastal paths and promenades could be highly dangerous as there is an increased risk of being swept out to sea. People are warned to stay away from the shoreline."
Bosses at energy network companies are due to face questions from MPs at some point when Parliament resumes next week.
They were criticised over the length of time it took to restore power to homes affected by storms over Christmas, while Prime Minister David Cameron was confronted by one angry resident in Yalding, Kent, during a visit to see the flood damage last week.
More than 150,000 homes were cut off after strong winds, torrential rain and flooding caused damage to power networks but today Mr Paterson said he expected the power companies to do their best to prepare for the latest storm.
Speaking on Sky News following the Cobra meeting in London, he said: "We are looking to have a combination of exceptional rain, wind and a surge in sea and high tides and so there are nearly 50 warnings put out around the whole of the west coast and south coast.
"We had a range of ministers from right across Government attending the meeting, who will be working very closely with local councils, power companies, utility and transport companies, making sure that all of those organisations are absolutely prepared for the bad weather that is coming."
Communities in parts of the South East were also braced for further deluges.
There were eight flood warnings and 95 flood alerts in the region, although none of them were deemed severe, according to the Environment Agency.
With more rain due to fall tonight and tomorrow, there was a further risk of flooding in Little Venice, Yalding, Kent, which had previously suffered over Christmas.
Sandbags were being deployed in the area by Maidstone Borough Council and residents in some roads were being advised not to return to their homes until further notice.
The AA said some drivers were failing to heed flood warnings, and that it has attended 1,500 call-outs from those stranded due to floods since December 23.
Darron Burness, head of the AA's flood rescue team, said: "The last week or so has been the AA's busiest period in recent times for flood call-outs and over such a large area of the country.
"Our patrols have seen it all in that time - including people ignoring road closure signs, blindly following their sat-nav or other drivers into deep water and 4x4 drivers naively thinking their car has amphibious qualities - and time and again they hear the same excuses that the driver didn't think the floods were very deep or that their car could deal with it.
"The bottom line is that flood water can be deceptively powerful and dangerous and there will be further tragedies unless people take heed of the dangers."
The 1,500 call outs include patrols being sent to 400 vehicles stuck in flood water, while the rest were vehicles that broke down after being driven through the water.
In Sussex, police warned that winds of up to 65mph along the coast, combined with high tides and low pressure, were likely to create storm surges.
Inspector Andy Kundert, Sussex Police's emergency planning officer, said there was a potential for coastal and inland flooding around the high-tide times of lunch-time and midnight tomorrow.
He warned people who may be tempted to swim or take a paddle not to, and said "enormous amounts" of shingle had been washed away over the past few weeks, meaning the sea has been pushing further up the beaches.
People were urged to look out for their neighbours, particularly if vulnerable. Mr Kundert said: "All the emergency services, local authorities and other agencies will be working to make sure the county is as safe as possible."