With the worst of the Christmas rains now behind us, and some drier and calmer weather being forecast for the next few days, it is interesting to take stock of the rainfall during the past four weeks as measured by meteorologists at the Department’s weather station, writes Dr Roger Brugge.
After a dry start to December 2013, a total of 165.3 mm of rain was recorded in the 28 days ending on 8 January 2014. This total represents just under three times the rainfall we would normally expect in such a period at this time of year – or a little over a quarter of all the rainfall we would expect to receive in a year, in just 4 weeks.
There was local flooding over Christmas Eve and on Christmas Day after prolonged heavy rainfall on saturated ground on 23 December, but with further wet weather in the following days local rivers such as the Kennet, Loddon and Thames quickly became swollen to capacity. Major local flooding started in earnest around New Year’s Day, another very wet day, as rivers began to break their banks.
How does this period compare to wet spells of similar length in past years? Examining the records from the University’s 106-year daily rainfall record, it falls some way short of the wettest four week period, which was the 28 days ending on 12 December 1929 when a total of 206.8 mm fell, 25 per cent more than the recent wet spell. This was part of a very wet period lasting from October 1929 to January 1930 – and the Thames Valley was badly flooded then too.
Within the last 40 years, similar events have occurred only twice – in December 1989 to January 1990 and in October to November 2000. Both events led to flooding, and December 1989 remains the wettest December on record at the University.
So, recent the recent rains are not without precedent in Reading – although there are not many such precedents in the last century that weather records have been kept at the university.