Global weather patterns may lead to severe flooding in February despite England remaining in drought, the Met Office has said.
Two-thirds of people at risk of flooding were unaware of the situation, the government said on Monday, as it embarked on an awareness campaign. This average cost to a flooded household is £30,000, figures show.
The end-of-winter floods would be a result of a weather phenomenon called La Niña – a powerful pattern influenced by cooler temperatures in the Pacific. This is what caused flooding in February, when storms damaged hundreds of homes.
The system, capable of setting off a chain reaction of extreme weather across the world, was likely to cause cold snaps at the beginning of the season and storms at the end of it, experts said.
The drought is also expected to have a large impact on flooding, with baked ground starved of rain all year less able to absorb heavy showers, meaning water runs off into properties or agricultural land.
Government agencies said the military was on standby to help should flooding become unmanageable for the Environment Agency and other bodies, with the risk expected to be particularly high at the end of winter.
Will Lang, the head of situational awareness at the Met Office, said there was a higher chance of cold, dry conditions from November until January but it was significant that the three-month forecast had not reached February.
This is because of La Niña. He said: “The risk of unsettled weather increases as we head into 2023. This is another La Niña winter, as it was last winter, so it would not be unusual if the wettest and stormiest part of the season with the greatest flood risk again [came] at that end of the season, in February, as it did last winter.”
Lang pointed out the country had a relatively dry December and January but in February it was hit with extreme storms.
“That pattern is broadly in line with what happens in the UK when we have La Niña in the tropical Pacific, so we get the knock-on effects that can tend to promote high pressure, which builds to the west of the UK in early winter,” he said.
“That can in turn block the Atlantic rain-bearing systems reaching us in that first part of the winter. And then we tend to get a return to low pressures when that higher pressure fades, and we get all our wet conditions in late winter.”
Caroline Douglass, the executive director of flooding at the Environment Agency, said the drought was likely to have made conditions worse for flooding, pointing out last year’s were “deadly”.
“It also means that when the soils are really dry, you get more runoff and you can have more impacts as a result of the drought,” she said.
Douglass added that weather records were being broken each year because of climate breakdown: “We did see records broken with some severe flooding in some parts, and around 180% of February’s rainfall fell within seven days.
“We are seeing more extreme events play out due to climate change. We are a country which has always had flooding … but we are seeing these [rainfall and river levels] records broken.”
Since 1998, England has had six of the 10 wettest years on record, and this year there were three named storms in one week for the first time.
“We know climate change is here – we are seeing more extremes,” Douglass said. “And I think we do have to be prepared. Two-thirds of people that are at risk of flooding do not know they are at risk and are unprepared. We know that from the surveys we do. So as we are seeing more extremes all the time, we do need people to understand the risk and check and sign up for flood warnings wherever possible.”
Lang added: “Winters are getting wetter, and within that the extremes are getting more extreme.”
