The incident was declared in Monmouth by South Wales Fire and Rescue Service at around 1.30am, with emergency services carrying out rescues, evacuations and welfare checks.
Check the weather forecast where you are
The fire service’s area manager Matt Jones said: “This is a large-scale incident, and our crews and partners have been working tirelessly through the night and into today to help those affected.
“I want to thank everyone involved for the professionalism and care they continue to show in very difficult circumstances.
“I would urge the public to avoid the Monmouth area completely. The flooding is significant, and we need to keep routes clear to allow emergency services to reach the people who need us most”
As of 5am, Natural Resources Wales issued four severe flood warnings – meaning “significant risk to life and significant disruption to the community is expected”.
These are in effect along the River Monnow in Skenfrith, Osbaston and Over Monnow, as well as the River Wye at Monmouth.
A further six flood warnings and 39 flood alerts have been issued across Wales, while dozens of flood warnings have also been issued across England.
The warning has been issued as Storm Claudia brought amber weather warnings and torrential rain to large parts of the UK on Friday.
Meanwhile, a yellow alert for cold weather has also been issued by the UK Health Security Agency (UKHSA).
Significant impacts possible
It affects five regions: East Midlands, West Midlands, North East, North West and Yorkshire and The Humber from 8am on Monday 17 November until 8am on Friday 21 November.
The UKHSA warns that “significant impacts are possible across health and social care services” including a rise deaths among those aged 65 and over, or those with health conditions.
The Met Office is forecasting that temperatures could fall below freezing in some areas of the UK next week.
A month of rain in 24 hours
Storm Claudia has brought heavy downpours and flooding with the Met Office warning some areas could see up to a month’s worth of rain in 24 hours. There has also been travel disruption.
Rail passengers are being told not to use Great Western trains between London Paddington and Bristol and South Wales because of flooding on the line.
Their services between Exeter St Davids and Barnstaple are not running for the same reason.
Avanti West Coast, Northern, CrossCountry, TransPennine Express, Transport for Wales and Chiltern are also reporting disruption or cancellations to their timetable.
An amber weather warning had been in force on Friday for parts of Wales, along with large areas of central England and some parts of northern England.
By 4pm on Friday, 81.8mm of rain was registered in Tafalog, Gwent – which is 60% of the monthly November average for the region.
The storm, named by Spain’s meteorological service, has triggered weather warnings in Spain and Portugal, and is affecting the Canary Islands.
Ireland’s meteorological service, Met Eireann, has also issued weather warnings, with significant rain likely in the southeast for Dublin, Wexford and Wicklow into Saturday morning.
It warns that significant flooding is possible along with hazardous travel conditions.
Meanwhile, a yellow weather warning for rain remains in place until 6am on Saturday, for most of Wales, as well as an area of England roughly south of York.
Some areas could expect 30 to 50mm (1.2 to 2in) of rainfall widely, with 100mm (3.9in) for parts of southeast Wales.
A separate yellow warning applies from midnight until noon on Saturday across Counties Down and Armagh in Northern Ireland.
The Met Office warns that 10 to 20mm (0.4 to 0.8in) is expected fairly widely, with potentially in excess of 40mm (1.6in) over the Mourne mountains.
