2 Nov 2012

Higher risk of winter floods after a wet summer

The Environment Agency, in conjunction with the Met Office, released its autumn/winter flooding outlook today.

It highlights that following the wettest summer in 100 years, there’s a higher risk of flooding for the rest of autumn and this coming winter in England and Wales.

This is a remarkable turn around of events given that earlier this year much of England was in the midst of an official drought following two consecutive winters of below average rainfall – winter being a time of year when rainfall is crucial in replenishing our water resources.

Normally during summer, it is very difficult for rain recharge water resources because evaporation rates are higher and growing plants take up a lot of water through their roots.

However this summer, due to the sheer volume of rainfall and the lack of any prolonged dry, hot spells, water has managed to percolate downwards into the aquifers, with a rapid and unprecedented turnaround of our water resources.

Whilst this turnaround has rid us of official drought status and hosepipe bans, it has put river, reservoir and groundwater levels at unseasonably high prior to the time of year when we experience our wettest weather.

In effect, the ability to cope with heavy rainfall in the coming months has been significantly reduced, and, as a result, the risk of flooding is elevated compared to a normal year.

What are the main concerns?

The Environment Agency and Met Office are warning that there is an increased likelihood of flooding from rivers in November and December, especially in south west England. Northern and western parts of England and Wales also have an increased risk after recent heavy rainfall.

Groundwater levels are also unseasonably high following this summer’s unprecedented rainfall. There is an increased risk of flooding from groundwater in the south and east of England with Devon, Dorset and Hampshire particularly at risk.

Flooding from surface water – where the amount of rainfall overwhelms the drainage network – is more likely as the ground is already saturated and unable to soak up any more water.

The risk of coastal flooding also increases at this time of year, especially during periods of high spring tides from 12-18 November and 12-18 December.

What is the weather trend for November?

November is a notoriously difficult month to forecast for too far ahead because it can experience such a range of weather.

Whilst balmy days with hints of an Indian summer can occur, early blasts of winter from the Arctic are just as likely.

Having had a look at the weather charts for the first few weeks of November, the general trend for the UK suggests a largely unsettled theme, with low pressure the dominant feature.

As a result, showers or longer spells of rain can be expected, with occasional drier spells in between.

There are also hints that it’s going to be quite cold, with brisk winds often varying between westerly and northerly direction, with snow possible – especially over the hills.

Fall in roads deaths due to wet weather?

Staying with the impacts of the wet weather, provisional government figures released yesterday show that the number of deaths on the roads this spring fell sharply, with an 18 per cent reduction compared to the same period last year.

The Department for Transport (DfT) commented that the wet weather experienced in this period is likely to have reduced levels of pedal and motorcycle traffic in particular.

They said that there is also evidence that the wet weather may have affected road-user behaviour through reducing traffic speeds.

Once again, this demonstrates the effect that the weather has on us all, even on a subconscious level.

Don’t forget, you can get the latest five day forecast on the Channel 4 Weather website and you can follow my updates on Twitter – @liamdutton

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2 reader comments

  1. John B Davies says:

    This coming winter is very difficult to forecast.

    The greatest relatively short term danger facing all nations is that the arctic will have even less sea ice at the end of summer next year 2013 than in 2012, unless there is a truly massive volcano which puts dust into the Stratosphere, and the end of summer sea ice area this year was the lowest on record.

    It is quite possible that the Arctic sea ice could melt completely by the end of summer 2013 but if this does not happen it will melt completely at the end of summer no later than 2015.

    This event will cause the earth to warm significantly because ice reflects the sun’s rays whilst water absorbs them. the resultant warming in the arctic will result in massive Methane releases from defrosting Methane Hydrates causing an immediate runaway greenhouse event.

    These events will lead to the deaths of most humans on the planet in the near future unless we take urgent action to save the climate and ourselves.

    John B Davies personal

  2. Nyge says:

    Didn’t I hear that the Antarctic Ice reached a record size this year?
    Wasn’t the bow and arrow going to be the end of the human race … then the Black Death came and went then it was “the bomb” …. and onto Swine Flu …. then we were going to be boiled alive by Global Warming now it’s the melting Artic Ice …. so what will it be after 2015 … death by Mars Attack ?
    So where can I go on holiday in 2016 ?
    Don’t loose any sleep my friends ….

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