After the driest period for nearly 50 years, the UK is now being warned to expect flooding from thundery showers which will offer little relief from the drought.
The flood alert follows days of extreme heat warnings and the official declaration of a drought after the longest nine-month dry spell since 1976. Meteorologists have warned that the downpours are not the good type of rain to combat drought and are more likely to cause flooding as water runs off parched land.
The heat wave is expected to break with a yellow thunderstorm warning covering most of the UK on Monday, all of England and Wales on Tuesday and most of southern and eastern England Wednesday.
The Met Office has warned of “torrential showers and possible disruptions” in some places, adding that homes and businesses could be “quickly flooded” and buildings damaged by floodwaters. He also indicated that power outages were possible.
The Environment Agency has also warned that properties could be flooded and travel could be disrupted by surface water.
John Curtin, the agency’s executive director of operations, tweeted that the UK was in “that twilight zone of having both flood and drought warnings”.
He said: “Heavy stormy rain over parched, hard ground will bring rapid runoff and an increased risk of flooding this week. But that will by no means fix weeks of dry weather, so most of England will remain in drought.
Professor Hannah Cloke, a hydrology expert at the University of Reading, said rainfall was ‘unlikely long enough or widespread enough to make much of a difference at some exceptionally low levels in reservoirs and rivers’ .
Dan Stroud, a forecaster at the Met Office, said: ‘We are coming to the end of a prolonged, very hot period, and the ground has been baked on, so it is extremely dry. The weather breaks down to a mix of heavy and thundery showers. And rain from really heavy downpours won’t be able to soak into the baked ground quickly. It is very difficult for water to enter, because it must expel air from the soil. So the dry soil is submerged very quickly, and then we get surface runoff.
He added: “What we really need is a continuous period of light rain or drizzle just to gently re-wet the ground. Intense downpours are not exceptionally helpful. It’s going to take a lot of rain over a long period of time to actually recharge aquifers and reservoirs.
Stroud said “almost anywhere” was at risk of thundery showers early in the week, but it was difficult to pinpoint exactly where. “Scotland and Northern Ireland were most at risk on Sunday. As we move into Monday, the risk develops first across Wales and the South West and then more widely across the 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 parched soil is resistant to water absorption, making flash floods more likely.
Rob Thompson, who demonstratedsaid, “Dry, parched soil does not allow water to enter as efficiently as already moist soil…Because soil resists water entry, water stays on the surface, to hit the slopes or just sit in a pool.”
An official drought was declared across eight regions of England on Friday by the National Drought Group.
Three water companies – Welsh Water, Southern Water and South East Water – have imposed watering 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 a teenager died on Saturday after stepping into the sea at Skegness after temperatures reached over 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 struggled in the water.
Two men suspected of arson have been arrested 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 forest setting a small fire, police said.
Norfolk Police said two men, both aged 44 and from Boston in Lincolnshire, were arrested on suspicion of arson and criminal damage and taken to King’s Lynn for questioning.