Thousands have had their Christmas travel plans disrupted and around 75,000 homes are still without power as severe weather continues in the UK.
Southern England has been badly affected, with floods in Surrey and Kent. Some homes may not have power until Boxing Day.
Trains have been cancelled and there were delays and cancellations at Gatwick Airport.
North-west Scotland has been hit by high winds.
In Devon, a man has died after jumping into the River Lemon to rescue his dog.
Witnesses saw the 46-year-old enter the river before being swept away, police said, and he later died in hospital. The dog escaped unharmed.
There is an Environment Agency severe flood warning - which means a danger to life - at the River Mole at Leatherhead in Surrey, with already high levels of water expected to peak around midnight.
About 75,000 homes were still without power across the UK late into the evening on Christmas Eve, after problems with power lines during the stormy weather.
Engineers were working into the night and over Christmas Day to get people reconnected, the Energy Networks Association said.
Power supplier Southern Electric said 44,000 of its customers remained without power, with West Sussex, southern Hampshire and Dorset worst hit.
About 19,500 could still be without power into Christmas Day, it said.
UK Power Networks, which supplies power to eight million people in the south of England, said thousands in Kent, Surrey and Sussex were without power as of 18:00 GMT.
It said it was aiming to restore power to everyone by the end of Boxing Day, but those whose power was not on by midnight on Christmas Eve should make contingency plans on the basis that power would be off for Christmas Day, it said.
Around 800 homes in the north of Scotland are also without power, mainly around the Deeside area, Buchan, Fort William and Wick - down from 3,500 earlier in the day.
Meanwhile a firefighters' strike was held running between 19:00 GMT and 00:00 in England and Wales.
But the flooding was declared a "major incident" in Surrey and Kent, and striking crews were recalled.
The severe weather caused disruption at some airports. At Gatwick, a power cut at the north terminal left several thousand passengers stranded, with delays and dozens of flights cancelled.
All flights due to depart from the north terminal after 13:00 GMT were moved to the south terminal, apart from those from British Airways - but the moved flights were delayed and others cancelled.
BBC Newsbeat reporter Declan Harvey reported "tired, cranky and angry" scenes with people stuck at the airport for 11 or 12 hours.
No trains ran to or from the airport for most of the day because of fallen trees on the line and disruption across the network - which caused a "massive queue" of people trying to leave the airport.
Some passengers faced the prospect of waking up at Gatwick on Christmas morning. A spokesman said staff were doing all they can to look after those stranded. The local hotels were mostly full, but the airport was providing refreshments and bedding.
Around 90 flights are due to leave Gatwick on Christmas Day, and the airport said no delays were anticipated, although passengers were advised to check with their airlines before setting off for the airport.
"We remain incredibly apologetic and are desperately trying to put things right but it will take the time it takes in terms of getting it right," a spokesman said.
Meanwhile, there was widespread disruption to rail services, with delays and cancellations on numerous lines.
Network Rail said the storm had caused even more damage than that caused by the St Jude's storm of October, and that scores of line blockages and over 200 trees had been removed over a period of 24 hours.
And it warned that planned improvement work might also be delayed.
"We will release more details once we have looked more closely at the schedule," said Robin Gisby, managing director of network operations.
Prime Minister David Cameron tweeted: "I'm across plans to get electricity to many without power. My thoughts are with them and those facing travel problems this Christmas Eve."
Christmas Day ferry
Many ferry services are still disrupted, including services between Scotland and Northern Ireland, and the Isle of Man Steam Packet ferry crossings. The company has said it will take the unusual step of operating a Christmas Day sailing.
In other developments:
- Police have named a man who died in Cumbria on Monday as Simon Martindale, 48. from Lancaster. He was seen with his dog in the River Rothay in Ambleside at around 14:25 GMT on Monday but he was swept away by the fast-moving water. A woman also died in storms on Monday - in Gwynedd.
- West Midlands Ambulance Service says a three-car crash that left a woman dead near Shrewsbury, Shropshire, happened in "difficult weather conditions"
- Two sailors - one French, one Swiss - were rescued after their racing yacht was damaged by 30ft waves and Force 10 winds off Land's End
- Fire crews have been dealing with flooding across south and west Wales, while investigations are continuing into the death of the woman in Gwynedd.
- In Dorset, 30 people trapped in cars by flood water were rescued by fire crews
- In Devon and Cornwall, several properties have been flooded, while some homes are without power
- More than 6,000 homes are without power in East Anglia, hundreds have no power in Somerset, and 50,000 homes in Hampshire and the Isle of Wight have been cut off
- A man is in hospital after being trapped under a fallen tree in St Martin, in Jersey
- The London Fire Brigade says it received five times the usual number of emergency 999 calls - 853 in total - on Monday night, meanwhile a giant "snow globe" around the Eros statue in London's Piccadilly Circus burst in the high wind
- Because of the disruption caused by the weather, the Isle of Man Steam Packet Company will sail on Christmas Day for the first time since the 1970s.
- Midnight mass services have been cancelled in churches throughout the southern Hebrides
As well as the severe flood warning for Leatherhead, the Environment Agency has about 130 flood warnings in place for England and Wales - signifying that flooding is "expected", and more than 250 flood alerts, where flooding is "possible".
The Scottish Environment Protection Agency has about two dozen flood warnings in place but no severe flood warnings.