18/02/2008 - Headlines - Environmental
Britain experiencing more heavy downpours
Researchers have confirmed what many of us already suspected - heavy downpours are becoming more frequent at all times of the year across the UK.The study from the University of East Anglia (UEA) showed this increase in the intensity of rain and snowfall had also led to more frequent flash flooding throughout the country.
The scientists from the UEA's Climatic Research Unit said it was not yet known what was causing more heavy rain events, but that they would be carrying out more research to see if man-made climate change was contributing to the rises.
In recent years various climate experts have suggested that global warming would produce an increase in rainfall as warmer air was able to draw up more water vapour.
According to data gathered by the UEA's Climatic Research Unit, the amount of winter precipitation coming from heavy rain or snow had risen from around 7% of the total in the late 1960s to around 12% in the last decade.
Flash floods
The study, published in the International Journal of Climatology, found similar increases in heavy rainfall were evident in spring and to a lesser extent in autumn.
Declines in heavy summer rainfall events appeared to have ended during the 1990s, with more recent figures suggesting a return to typical levels of intense falls in the past decade, the scientists said.
The researchers used data stretching back as far as 1900 from 600 rain gauges around the UK and classified each day's rainfall into one of 10 categories ranging from drizzle to a downpour. While the number of rainy days did not increase, intensity of rain rose across all regions of the UK.
Dr Douglas Maraun, one of the scientists who conducted the study said: "Heavy rain on one day could cause so-called flash floods, when the rain is so heavy it can't run off into the ground. When the rainfall increases we get more of these flash floods.
"So far it is not clear what causes these trends and variations. In the next stage of our study we will be looking at possible physical mechanisms and whether man-made global warming is contributing."
The research was funded by the Natural Environment Research Council as part of the 'Flood Risk from Extreme Events' programme, which hopes to improve predictions of flooding - from minutes through to decades ahead.