'Exceptional' storms are going to bring more flooding misery to Britain.
Appalling weather is expected across the whole of Great Britain and Northern Ireland, forecasters say.
There is high risk of flooding expected around Friday morning's high tides, posing a significant risk to coastal towns and villages.
The Environment Agency (EA) has issued 21 of the most serious severe flood warnings in place, issued when there is a threat to life or property, affecting the South West, Gloucestershire and Wales.
Homes in Newport were evacuated last last night because of the risk of flooding as Wales prepared for the highest tides in 17 years, ITV News said.
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Residents at the Lighthouse Park Estate were taken to a nearby leisure centre as a precaution, and coastguards have been warned of a storm bringing 70mph winds.
People living in Ilfracombe were joined by emergency services during the night as they gathered sand from beaches to build flood defences.
The EA has also issued 188 flood warnings across England and Wales and a further 233 flood alerts.
Heavy rain and winds gusting up to 60mph are due to hit western areas, prompting fears of widespread disruption.
The bad weather is compounded by high tides this morning, with the risk of flooding expected for between two and four hours either side of high water.
Waves of more than 30ft (10m) are expected to hit Devon and Cornwall, the BBC said, with authorities declaring in a "major incident" and warning people to stay away from shorelines, where there are 14 severe flood warnings and 60 flood warnings.
In Belfast, Northern Ireland police have been delivering sandbags and have issued a warning to people in the Sydenham and Docks areas to prepare for potential flooding and the possibility of evacuation.
Emergency services will be under increased pressure with a Fire Brigades Union strike today between 6.30 and 8.30am.
Environment Secretary Owen Paterson, who chaired a meeting of the Government's Cobra emergencies committee, yesterday warned energy network companies to be prepared, 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.
In a statement on its website, the EA said: "The flood risk will extend along the UK coastline from north-west England, through Wales and south-west and southern England. Areas particularly at risk include the Isles of Scilly, the north and south coasts of Devon and Cornwall, Dorset and the coastline of Wales."
The storms have already claimed at least two lives. The body of a 27-year-old man from Surrey was found on Porthleven Sands beach in Cornwall. 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 carried out for a man who is believed to have fallen into the River Stour, near Iford Bridge in Christchurch.
In Scotland heavy rain and gusts of up to 60mph could sweep across the country today, bringing further disruption after days of wet weather.
High tides and a storm surge have increased the risk of flooding in the Firth of Clyde, according to the Scottish Environment Protection Agency (Sepa).
A tidal surge is expected around lunchtime, particularly around the Firth of Clyde, Solway Firth and Ayrshire, the Scottish Government said.