Major incidents have been declared in south Wales and parts of England, as Storm Dennis batters the UK.
Dyfed Powys Police said a man had been found dead after falling into the River Tawe, while South Wales Police said it was dealing with “multiple” landslides and floods – some trapping residents.
Homes have also been flooded in Herefordshire, where one resident said the storm had hit “like a tornado”.
More than 300 flood warnings have been issued across the UK.
There are currently four severe flood warnings in England and two in Wales, which mean there is a danger to life.
Flooding ‘risk to life’ in Worcestershire
How do I stop my trampoline flying off in a storm?
What do we know about Storm Dennis?
A record number of flood warnings and alerts were issued for England on Sunday, according to John Curtin, the Environment Agency’s head of floods and coastal management – reaching a combined total of 594 shortly before midday.
Jessica Falk Perlman, who is on holiday with her family in Crickhowell, Powys, to celebrate her mother’s 60th birthday, told BBC Radio 5 Live that firefighters woke them at 04:00 GMT to tell them they were being evacuated because the River Usk had burst its banks.
Media captionJessica Falk Perlman in Crickhowell, south Wales: “Our cars are completely underwater”
But water quickly came flooding into their holiday home, forcing them upstairs and stalling their evacuation.
“The door of our house burst open and water came flooding in right up to the top of the stairs which was quite nerve wracking at the time,” she said.
“It’s well over the front door of the house, it’s flooded all the way up to the ceiling.”A bookcase in Amy Price’s Monmouthshire home was floating in floodwater
Amy Price, 20, said her family were trapped in the upstairs of their home in Llanover, Monmouthshire, because water on the ground floor had reached as high as the light switches.
“The river started rising about 1am and at 3am it started coming into the house,” she said.
“We started sweeping the water away and then at 6am the river started coming over the bank.”
South Wales Police said emergency services were working with local organisations to ensure the safety of people in communities cut-off by flooding, and to minimise damage and disruption.
Emergency centres have been set up for those who have been displaced.
Assistant chief constable Jennifer Gilmer praised rescue workers’ professionalism and advised people “not to panic”.
Meanwhile, in Herefordshire, the council said it was working with the emergency services, the Environment Agency and health partners to assist residents.
It urged people to avoid unnecessary travel and check on their neighbours, and said “rest centres” are being set up for those who need to be evacuated.
Tracey Newman’s home in Nantgarw has been inundated with water
Sarah Bridge, 55, compared Storm Dennis to a tornado and said water had flooded her home in Pontrilas in Herefordshire despite specialist flood doors, reaching her knees.
“It’s heartbreaking,” she said. “The kitchen is completely flooded, I can hear things floating about downstairs.”
A major incident has also been declared after flooding at properties in Lowdham in Nottinghamshire.