Torrential rain from Storm Dennis has swelled British rivers to "exceptional" levels - and smashed 200-year-old records.
And the Environment agency warns more woe is yet to come after whole communities were left devastated by flood waters
As the EA warned of more terrible downpours later this week, it announced the river level in Hereford has reached the highest on record.
Speaking from Worcester, the EA's West Midlands environment manager David Throup told Sky News: "I think it's peaking now in Hereford, the levels that you've got there are truly exceptional levels, they are the highest levels we've ever recorded on the River Wye and those records go back 200 years, so we are talking very, very exceptional levels.
"Here in Worcester, the River Severn is also at a level that is similar to the big floods in 2007."
Communities across the country are counting the cost of the weekend's storm which has left more than 400 properties flooded.
Among the worst affected areas were South Wales, Herefordshire, Worcestershire and Shropshire where major incidents were declared.
Around 1,000 staff were on duty, with 5km of flood barriers deployed and 90 pumps in action, the EA said.
It warned the flood risk continues, with further heavy rain forecast in the north of England for Wednesday and Thursday, possibly falling on already flooded areas.
One woman, swept away by floodwater near Tenbury in Worcestershire on Sunday, was feared dead by police as a search resumed on Monday.
Emergency evacuations were also under way in Hereford, where the River Wye reached its highest level on record.
The aftermath of the storm caused transport disruption on Monday, as train lines and roads were blocked by flooding and fallen trees.
The AA said nationally it had attended more than 400 vehicles stuck in water or mud over the weekend, more than double that under Storm Ciara a week ago.
Hereford residents were advised that flooding could trigger periodic power cuts and some roads were closed.
Speaking in Worcester, the EA's David Throup, West Midlands environment manager, told Sky News: "I think it's peaking now in Hereford, the levels that you've got there are truly exceptional levels, they are the highest levels we've ever recorded on the River Wye and those records go back 200 years."
He added: "Here in Worcester, the River Severn is also at a level that is similar to the big floods in 2007."
As of 3.30pm on Monday, six severe "danger to life" flood warnings from the EA were in place for the River Wye at Blackmarstone, Hereford, and at Hampton Bishop; the River Severn at Uckinghall and at New Street and Waterside, Upton upon Severn; and the River Lugg at Hampton Bishop.
The agency's executive director of flood and coastal risk management, John Curtin, tweeted that 420 properties were flooded by Storm Dennis and 18,500 protected, with both figures expected to rise.
He indicated that 800 properties were flooded by Storm Ciara.
Locals in the inundated area around Hereford described "devastating" flood scenes that struck roads, a business park, the railway line and homes.
Greg Smith, who took drone images of the flooding, said: "I've never seen anything like this."
Meanwhile, residents living near Eastham Bridge in Worcestershire described 48 hours of chaos as they lost count of the number of vehicles - including a fire engine and a petrol tanker - caught in floodwaters.
Over in South Wales, one of the worst-hit areas was the village of Nantgarw, near Cardiff, where entire streets were left underwater from the early hours of Sunday morning.
Jeanette and Rachel Cox had a "terrifying" evacuation from their home in Oxford Street after waking at 4am to the floodwater.
"Everything downstairs has completely gone," said 68-year-old Mrs Cox, who was only able recover a wedding day photo of her with husband Bill, who died from cancer in 2009.
Visiting the flooded village of Trehafod, near Pontypridd, Plaid Cymru leader Adam Price criticised the Welsh Government's level of investment in flood defences, saying the weekend's events were a "wake-up call".
Natural Resources Wales said provisional data indicated the River Taff at Pontypridd had reached its highest level for over 40 years.
Youth climate strikers said they had to cancel their first ever national conference, with delegates coming from across the UK, due to serious flooding in Staffordshire.
The Prime Minister resisted calls to chair a meeting of the Government's emergency committee, Cobra, to tackle the flooding crisis, despite criticism from the Labour Party.
Luke Pollard, shadow environment secretary, said it was a "disgrace" that Boris Johnson had "refused" to visit affected communities.
Asked why Mr Johnson was not making personal visits, a Number 10 spokesman said he was receiving regular updates and that Environment Secretary George Eustice was leading on the issue.
Mr Eustice defended the Government's response, saying it was not possible to protect every house from flooding and pointed to £4 billion of funding committed to flood defences in the next five years.
Meanwhile, local authorities hit by flooding will be able to recoup some of their costs via emergency financial assistance available through the Bellwin Scheme, the Government said.
A record number of flood warnings and alerts, more than 600, were issued by the EA across England on Sunday, with this falling to below 500 on Monday afternoon.
The Met Office has issued two yellow weather warnings for snow and ice over parts of Scotland from 6pm on Monday, with further warnings of persistent rain in Wales for Wednesday and Thursday.
