Tuesday, 3 January 2012

When the Wind Blows

How the mighty have fallen -
Mature tree in Pollok Park destroyed
in December storms
It has been fairly windy in Scotland over the past year. Back in May, unseasonable storms battered the country causing one fatality, power outages, travel disruption, damage to crops and felling many trees.  We do not normally have such high winds during the spring and summer when the trees are in full leaf so they were more susceptible to damage and many mature trees were lost.

The next big storm was in September when the tail end of Hurricane Katia brought heavy rain, flooding and more trees down. It was not nearly as severe as Huricane Irene that struck the north east US a couple of weeks earlier but it still caused at least one fatality and significant disruption.

A relatively calm and mild but wet autumn followed as local government prepared for heavy snow like that which caught them out last year. Then came hurricane force winds on the 8th of December. They had been forecast a few days in advance with the Met Office issuing red alert and the authorities were taking no chances: closing most schools, recommending that people don't travel at all if possible and leave work early to avoid the most severe winds.  The main concern was that the strongest winds were forecast to occur during the afternoon and into the evening rush hour, meaning more people on the roads, hence a greater probability of accidents, people getting stuck and congestion preventing the emergency service getting about.  More trees came down as expected, knocking out power lines, closing roads and disrupting trains but the ferocity of the storms were perhaps a little less than expected.

December continued to be blustery with strong gales on Christmas Eve causing some localised damage (a neighbour lost part of his shed roof) then the next big one hit on the third of January.  This time central Scotland was hit hard as were parts of England and Wales.  The forecast was for strong winds but only an amber alert, rather than the red alert issued for the 8th of December storms so people didn't expect it to be as bad.

The damage was widespread and dramatic:

  • 40 trees, including a 150 year old oak were blown over in Edinburgh's Botanical Gardens;
  • The Kingston, Erskine, Forth and Tay Bridges were closed to some or all traffic;
  • Most mainline train services were suspended;
  • Nearly 900 trees had been blown on to a short length of railway in Fife
  • 32 roads in Glasgow were closed due to fallen trees with more closed due to unsafe buildings;
  • More than 100,000 homes were without power, several thousand were still not connected two days later;
  • A power failure at a sewage pumping station in Renfrewshire caused untreated sewage to be discharged;
  • A metal roof blew off a tower block and landed on a house several streets away; and
  • A bus shelter was blown into a plane at Edinburgh Airport. 
One of many fallen tree in Pollok Park, taken 31/12/11
Some pictures here and here.

Is this sequence of storms just a result of natural variations in our weather patterns or is it an effect of climate change? A single event would certainly not be considered a trend but when do a series of events become a trend? Climate change theory indicates greater unpredictability of weather systems and the variability from last winter'e bitter cold to this winter's strong winds could be part of that unpredictability.

If it is a sign of things to come, how can we be better prepared? Stockpiling grit won't help in a gale nor will building flood defences. We could cut down corridors of trees to either side of all our roads, railways and power lines but that isn't practical or desirable.  We could inspect our existing buildings for loose masonry or poorly fixed tiles but no matter how good or how frequent an inspection a little frost or some moss could loosen something and a stray gust pull it off.

What do you think, should we expect more frequent severe storms or will the storms of 2011/12 be remembered in the same way as the great storm of 1987 (or 1953 or 1703, both before my time) as events that only happen every two or three decades? Have this year's storms even been as bad as previous ones, or do they only appear so due to mass media coverage, round the clock news and more information about incidents that we wouldn't have heard about twenty years ago?

Do we just face these storms and fix things up afterwards or do we need to develop more resilient infrastructure? If so, we should begin now but what target should we be chasing?

No comments:

Post a Comment