England could suffer "record-breaking" downpours every winter over next decade, the Met Office warns.
The weather bureau's new supercomputer has predicted there is a one in three chance of floods bringing chaos to at least one English or Welsh region each year.
Met experts say the increased risk comes from climate change and a higher recent incidence of extreme downpours.
Across the winter of 2013-14, a series of storms hit the UK leading to extensive flooding in many parts. Rainfall in much of southern England and the Midlands was the heaviest in 100 years, with the clean-up bill for the Thames valley alone topping £1bn.
December 2015 saw similar floods in the south-east, while Storm Desmond hit the north-west causing widespread flooding and storm damage.
The Met had to use its supercomputer to calculate the risks of further downpours over the coming ten years, as the changes to the climate have made past record less reliable.
It said the computer allowed experts to model relevant data from 1,750 winters, rather than information from 35 relevant winters that had been available to it.
The bureau's analysis revealed a 7% risk of record monthly rainfall in the south east region in any given winter.
It added that when other English and Welsh regions were considered, the risk of at least one of them being swamped by a record deluge rose to 34% chance.
The Met's Dr Vikki Thompson said: "Our computer simulations provided one hundred times more data than is available from observed records.
"Our analysis showed that these events could happen at any time and it's likely we will see record monthly rainfall in one of our UK regions in the next few years."
This new research approach has been dubbed the 'unseen' method, to emphasise that this work anticipates events that have not yet been observed.