The widespread snow, ice and wind that caused extreme disruption to much of the UK this week followed the driest February in 30 years and unseasonably mild temperatures.
Across the month, England recorded its lowest amount of rainfall since 1993 and eighth lowest since records began in 1836. The driest county, Essex, received just 3.5mm of rain in the entire month — or 8 per cent of its average.
Wales recorded 22 per cent of its average rainfall, Northern Ireland 34 per cent and Scotland 69 per cent, meaning that the UK as a whole experienced well under half of its normal level of precipitation for this time of year.
Temperatures across the UK in February averaged 5.8C, the equal fifth warmest since records began in 1884, according to the Met Office. Those dry, mild conditions cause particular concern for groundwater levels.
In the UK, the period between October and March is known as the recharge season, when evaporation is generally lower than rainfall and water levels recover from summer lows.
According to the UK Hydrological Outlook, groundwater levels responded quickly to February’s low rainfall with a record breaking low recorded in Greenfield Grange, south Wales.
By the end of February, much of the country was in water deficit, with additional rainfall required in the coming months to restore subsurface water levels to normal conditions. The latest forecast suggests that groundwater levels are likely to be “notably low” in parts of southern England in the months ahead.
The sudden swing from the extreme dryness of February to March’s wetter conditions comes as new research suggests Britons will need to prepare for greater frequency of extreme rainfall events that can lead to flash flooding.
The Met Office defines an extreme event as one where rainfall intensity exceeds 20mm per hour. These are not unknown — 40mm of rain fell at Kew Gardens, London in July 2021, flooding the underground.
These extreme events could be up to four times as frequent by 2080 under a high greenhouse gas emissions scenario, compared with the 1980s, according to the Met Office.
The research also suggests that the intensity of downpours could increase by between 5 per cent to 15 per cent for each degree of regional warming, with the north-west of the UK being most affected.
Extreme rainfall events in north-west Scotland could be almost 10 times more frequent in 2080 compared with the 1980s, according to the modelling.