Households have been urged to pack ‘grab bags’ with valuables and essential items as three million households face the risk of flooding in the coming days.
The second prolonged heat wave of this summer ended abruptly Monday as thunderstorms lashed some areas with nearly three inches of rain.
Forecasters warned of an “incredible deluge” this week after the driest July on record and the driest first half of the year in decades caused drought in parts of the UK, leaving the land parched.
The Met Office issued a yellow thunderstorm warning for most of the country on Monday and Tuesday as conditions could cause flash flooding, transport disruption and power outages.
It will remain in place for southern England on Wednesday, where communities could be cut off by flooded roads, and the possibility of deep or fast-flowing flooding could be life-threatening.
More than three million homes in England are vulnerable to surface water flooding, the Environment Agency estimates, with a further 300,000 at risk in Wales and Scotland.
People who live in ‘low-lying properties’ should ensure their valuable items are ‘ready to use’ or ‘on a higher level of their house’, due to the current high risk of flooding.
Speaking to Sky News, Met Office meteorologist Clare Nasir said: “For low-lying properties, which may have been built on a flood plain, yes, there is a risk of flooding to properties.”
“Get all your documents, whether it’s your mobile phone, your passport, etc., all those things you don’t want to be damaged by floods and make sure they’re ready to use or on a higher level of your house.”
He added that downpours overnight and this morning are “the wrong kind of rain we need for the ground” as the ground is too hard to absorb it.
The forecaster continued: “What we’re looking for is kind of a continuous rain, moderate rain, rather than this incredibly intense burst, which is currently moving into the more southern areas of England.”
‘So we’re not out of the woods yet.’
Heavy rain caused flooding in areas of Cornwall and Devon on Monday afternoon, while thunderstorms developed in east coast counties including Essex, Suffolk and Lincolnshire.
Met Office meteorologist Tom Morgan said most places remained dry throughout the day, but added: “There have been areas of the country that have predominantly seen heavy rain today, in the south west of England.”
“We’ve seen some flooding in parts of Cornwall and Devon,” he said, adding there has been “very difficult driving conditions, flash flooding, hail with thunderstorms and some lightning.”
He said the flooding is also “causing the possibility of some power outages and some possible flash flooding, particularly in towns and more urban areas.”
“There are also thunderstorms in the east coast areas in Suffolk, Essex and Lincolnshire,” he said, but added that they are not expected to have a significant impact causing difficult driving conditions.
Morgan continued: “There is as much potential as [Tuesday] be as impressive as it was today.’
Flood warnings were also issued for parts of west London near the Thames, including Richmond, Chiswick and Putney, but have since been removed.
Speaking on Monday, London Mayor Sadiq Khan said: “We learned a lot from last year in July when there was flash flooding caused by a huge amount of rain – the equivalent of two months of rain – in just a couple of hours and houses of people, businesses and public transport were flooded.
“Speaking to the Met Office, the Environment Agency and many others, we are concerned that in the next few days we may see a large amount of rain in a short period of time that could lead to flash flooding.
‘I have written to tens of thousands of Londoners who live in homes that could be affected by flash flooding.
“My message to Londoners is to contact the Floodline, go to your local authority’s website to see what you can do to reduce your chances of being flooded, but also to minimize the consequences for yourself,” he said, advising people who also verify that they are insured and what those details are, as well as prepare a goodie bag.
Mr Khan said: ‘[We are] working closely with the water companies, the fire brigade, Transport for London, councils and other partners to make sure we are as prepared as possible, but the bad news is there could be flash flooding if it rains heavily for a period short of time.’
Earlier, Professor Hannah Cloke, a hydrology expert at the University of Reading, explained why there is a chance of flooding in drought-affected areas.
She said: “The ground is really dry and when it’s that dry it acts a bit like concrete and water can’t get in, so it drains straight away.”
“There’s the damage to homes and businesses that these floods can cause, and the inconvenience with transportation disruptions, but if it’s very heavy in one place, it can also be very dangerous.”
On how it could affect cities and towns, he said: “If it rains a lot in a city, the drainage system can cope to some extent, but if it rains a lot, it can overwhelm the system, the rain can’t run.” away fast enough.
In rural areas, Professor Cloke said this type of flooding often hits low spots on roads and under bridges, adding: “It’s very dangerous to drive through flood water.”
Explaining why this heavy rain will not relieve drought-stricken areas, he said: “It really is a drop in the ocean.” It doesn’t soak into the ground, which is how we really need it.
We need it back on the system where it can be stored. We really need a long winter of rain to replenish this.
Meanwhile, Christine Colvin, director of advocacy and engagement at the Rivers Trust, said there is a risk that people will not take the drought seriously in the coming days “just because it rains”.
“We want people to keep this rain event in context and part of the big picture, and the big picture is that we’ve actually still had an incredibly dry year and a dry summer, and it’s going to take sustained rain to replenish our supplies.” said.
‘Just because it rains, doesn’t mean the drought is over.
“It seems very counter-intuitive, but it will take sustained rain to replenish the supplies we actually use, which are aquifers and managed storage in our reservoirs.”
Get in touch with our news team by emailing us at email@example.com.
For more stories like this, check our news page.