After the driest period for nearly 50 years, the UK is now being warned that flooding is expected from downpours that will offer little relief from the drought.
The flood warning follows days of extreme heat warnings and the official declaration of drought after the longest nine-month drought since 1976. Forecasters warned that downpours are the wrong type of rain to deal with drought and are more likely to cause flooding from water running over dry land.
The heatwave is expected to break with a yellow warning for thunderstorms covering most of the UK on Monday, all of England and Wales on Tuesday and most of southern and eastern England on Wednesday.
The Met Office warned of “torrential rain and possible disruption” in places, adding that homes and businesses could be “quickly inundated” and buildings could be damaged by floodwater. He also said power outages are possible.
The Environment Agency also warned that properties could be flooded and that surface water could disrupt travel.
John Curtin, the agency’s chief operating officer, tweeted that the UK was in “that twilight zone with flood and drought warnings”.
He said: “Heavy thundery rain over dry, hard ground will lead to rapid run-off and an increased risk of flooding this week. But this will do nothing to correct weeks of dry weather, so most of England will remain in drought.”
Teacher Hannah Cloke on the banks of the River Thames in Sonning, Berkshire. Photograph: Peter Nicholls/Reuters
University of Reading hydrology expert Professor Hannah Cloke said the forecast rain was “unlikely to be of long duration or widespread enough to make a big difference to some exceptionally low levels in reservoirs and rivers”.
Dan Stroud, a Met Office forecaster, said: “We are coming to the end of a long, very hot spell and the ground has baked so it is extremely dry. The weather is breaking down into a mix of intense and thunderous showers.
“And the rain from very heavy downpours won’t be able to get into the terra cotta quickly. It’s very difficult for the water to actually get in, because it has to force the air out of the soil. So the dry soil gets overwhelmed very quickly and then we get surface runoff.”
He added: “What we really need is a sustained period of light rain or rain just to gently rewet the soil. Heavy downpours are not exceptionally helpful. It will take a lot of rain over an extended period to recharge the aquifers and reservoirs.” .
Stroud said “pretty much anywhere” was at risk from the impact of rain earlier this week, but it was difficult to determine exactly where.
“Scotland and Northern Ireland were most at risk on Sunday. As we move into Monday, the risk develops initially in Wales and the south-west, then more widely across England during the afternoon and evening.”
Last week, the University of Reading released a video of a simple experiment involving three cups of water to show how dry soil is resistant to water absorption, making flash floods more likely.
Rob Thompson, who led the demonstration, said: “Dry, dry soil doesn’t let water in as effectively as already wet soil… because soil resists water ingress, water it is on the surface, for running on slopes or just sitting in the pool.”
The National Drought Group declared an official drought in eight areas of England on Friday.
Archie Bland and Nimo Omer take you through the top stories and what they mean, free every weekday morning
Privacy Notice: Newsletters may contain information about charities, online advertisements and content funded by third parties. For more information see our Privacy Policy. We use Google reCaptcha to protect our website and Google’s Privacy Policy and Terms of Service apply.
Three water companies – Welsh Water, Southern Water and South East Water – have imposed hose bans, while Yorkshire Water has announced a ban will start on August 26 and Thames Water is planning one in the coming weeks.
Lincolnshire Police confirmed that a teenager died on Saturday after getting into trouble at sea in Skegness after temperatures reached more than 30C in parts of England.
A body was also found in a lake in Doncaster on Saturday, following reports that a man in his 20s had been in trouble in the water.
Two men have been arrested on suspicion of arson after a fire broke out in Norfolk.
Emergency services were called to Bawsey Country Park, near King’s Lynn, at around 11.40am on Sunday after a disposable barbecue was “thrown” into the woods causing a small fire, police said.
Norfolk Police said two men, both 44 and from Boston in Lincolnshire, had been arrested on suspicion of arson and criminal damage and had been taken to King’s Lynn for questioning.
In Scotland, customers were evacuated from a Tesco supermarket in Inverness after water came in through the roof on Sunday afternoon.
Videos posted on social media showed ceiling tiles falling and water pouring in, covering most of the supermarket’s floor.
The area was hit by heavy thunderstorms and torrential rain for most of Sunday.
A Tesco spokesman said on Sunday evening: “Our Inverness Inshes Extra store is temporarily closed while we assess some damage to the roof. We apologize for the inconvenience. We are working to reopen as soon as possible.”
A car park near the supermarket, located on the Inshes shopping park, was also flooded, as was a nearby Vue cinema.