Future of the Railways in Global Climate Change Conditions

[whole diary]

[didcotdean]

... same Met Office that, back in November, was predicting that ^precipitation^ for the three months between December and February was likely ^to fall into the driest of our five categories^, and would more likely than not take the form of snow ... the same Met Office that in March 2012 was assuring us that April to June that year would be drier than average, with April the driest month, just before we enjoyed the wettest April ever...

Interesting to look at the March 2012 forecast which is at here rather than have it distilled through someone else. It actually states the following probability:

The probability that UK^▸ (United Kingdom) precipitation for April-May-June will fall into the driest of our five categories is 20-25% whilst the probability that it will fall into
the wettest of our five categories is 10-15% (the 1971-2000 climatological probability for each of these categories is 20%).

So the Met Office didn't 'assure' that it would be drier than average, only that this was a more likely possibility. In the end the 10-15% chance won. It also says:

However there are hints from some computer model forecasts that as we move through May and on into June the jet
stream over the North Atlantic may tend to edge southwards, which, if it happened, would probably lead to an increase in rainfall across the UK.

The three month outlook for November 2013 ^ January 2014 is here. The precipitation indication:

The probability that UK precipitation for November-December-January will fall into the driest of our five categories is close to 15%
and the probability that it will fall into the wettest category is approximately 25% (the 1981-2010 probability for each of these
categories is 20%).

Ultimately these are trend indications for contingency planning purposes.

[Chris from Nailsea]

An update, from the BBC^» (British Broadcasting Corporation - home page):

Somerset floods: Four pumps back on after river damage

Half of the high capacity pumps being used to shift flood water in Somerset are working again after being switched off due to riverbank damage.

The eight pumps at Dunball are being used to bypass the sluice by the River Parrett and King's Sedgemoor Drain.

To protect the banks of the Parrett from the high volume of water being discharged, rocks in metal cages have been placed to absorb the impact.

It is not yet known when the remaining Dunball pumps will be turned back on.


Heavy duty pumps are damaging the banks of the River Parrett

A total of 13 Dutch pumps were brought in by the Environment Agency to speed up the movement of water from the Somerset Levels drainage channels.

Five pumps at Beer Wall near Bridgwater are still waiting to be turned on.

The original plan was to run the pumps at Dunball for a few days before levels had been reduced enough for the ones at Beer Wall to be turned on.

But those plans have been delayed due to the riverbank damage caused on Saturday.

The agency now expects the Beer Wall pumps to be turned on towards the end of this week.

[JayMac]

Anyone else looking at that picture from the BBC^» (British Broadcasting Corporation - home page) and thinking 'The Guns of Navarone'?

Just me? 

[Chris from Nailsea]

Just you. 

Five pumps at Beer Wall near Bridgwater are still waiting to be turned on.
. . .
The agency now expects the Beer Wall pumps to be turned on towards the end of this week.

That's what I'm waiting for ... 

[stuving]

I have a book called "The Berkshire Weather Book", put together mainly from newspapers. It includes Thames floods even if the rain in them fell upstream. I've gone through trying to pick out the years for which it records major floods, to give you an idea how many there have been (but I've probably missed some) . The book came out in 1994.

Of course the amount of rain that produces a major flood has gone up as work has been done on the river, but all these river floods would have flooded a similar number of houses to this year. Places like Old Windsor would of course get some flooding most years, and before 1900 only the bigger ones are in the book.

Major Thames floods:
Mar 1774*
Jan 1809* (snowmelt)
Nov 1852* ("Wellington's flood")
Nov 1875
Nov 1894*
Feb 1897
Feb 1900 (snowmelt)
Feb 1904
Apr 1908 (snowmelt)
Dec 1914/Jan 1915
Jul 1920
Jan 1925
Jan 1926
Jan 1928 (snowmelt)
Jan 1936 (snowmelt)
MAr 1937 (snowmelt)
Mar 1947* (snowmelt)
Jan 1949 (snowmelt)
Jan 1951
1974
Dec 1979 (Boulter's weir blocked by barge)/Jan 1980
Feb 1990

The asterisked ones were the biggest - from reports, much worse than this year (on the Thames).
Looking at the 1920s, even the last ten years isn't exactly "unprecedented".

Major flash floods (may also give some river flooding):
Feb 1883 / 1901 / Jun 1903 / Jun 1910 / Apr 1913 / May 1932 / 1943 / Sep 1968 / Jun 1971 / Mar 1979 / May 1993