Monday, 18 January 2010

Last Tuesday's snow event

Writing about the better weather in my last post reminds me that I haven't commented yet on the snow event last Tuesday (the 12th) which caused so many problems for drivers in my two counties. I say "snow event", here tucked down in the valley we had no more than sleet that day. A depression coming in off the Atlantic had its weather fronts bumping into the existing cold air that was dominating the UK, a classic situation where substantial falls of snow can occur and one I've seen before a few times. It was very well forecasted by the Met Office and it was always evident that altitude would have a substantial affect on snow quantities.

For those not familiar with my two counties it has to be said that the topography has an absolutely enormous influence on the weather we experience. This weather can be incredibly local, one classic example being the rain that caused such havoc at Boscastle and Crackington Haven in August 2004. This flood was over a geographically small area, villages a few miles away were unaffected. The hills and valleys in the south west that please the tourist's eye (and mine it should be said) have always been a nightmare for road and railway builders. So far as the railway is concerned Brunel hugged the river estuaries and coast between Exeter and Newton Abbot. OK he kept the route pretty flat but we all know about the huge problems there have been with the sea wall at Dawlish!

The main road from Exeter to Plymouth, the A38, has to cross the Haldon ridge soon after it leaves Exeter. Now the top of Haldon is approximately 800 feet above sea level but it's not just drivers having to ascend that much from the Exeter direction that can create problems, it's the degree of steepness. In a much earlier life I was involved in road design and although it was decades ago I do recall that the maximum gradient for trunk road design was 1 in 25 (4% in modern parlance I suppose). I was never involved with 'Haldon Hill' but it wasn't possible I know to get remotely near that figure - I can't remember for sure but I think it was more like 1 in 14, very very steep for a trunk road. Unsurprisingly a third crawler lane was put in place for the uphill carriageway. A similar arrangement holds for the also very steep 'Telegraph Hill', the Torquay A380 route that forks off the A38 at Splatford Split at the bottom of Haldon Hill.

Exact details of the way traffic ground to a halt on these two notorious hills on Tuesday remain a little sketchy but it seems that the rain on the ridge quickly turned to snow, a lorry jackknifed on the A38, traffic stopped and couldn't get going again and because some vehicles started sliding whilst others tried to pick their way through the gaps the whole road system got clogged up making it really difficult for gritting lorries and snowploughs to get through to where they were needed. Result: vehicles stuck for hours and hours with nowhere to go. Eventually, somehow, things did get sorted out and thankfully nobody was hurt. A few comments from me then:
  • Although well forecasted the weather changed very rapidly at Haldon, many leaving Exeter in the rush hour I'm sure genuinely didn't perceive a problem just down the road.
  • The authorities seemed to be very tardy about officially closing Haldon Hill, the result being that traffic was just joining the queue with nowhere to go. As I heard it on Radio Devon it seemed that they were suggesting traffic could just about get through, that doesn't seem to be the case for the general public although police, fire crews and Dartmoor Rescue Group volunteers seemed to have got through. A very muddled picture.
  • There is an alternative coastal route from Exeter to Newton Abbot, a pretty lousy road in my opinion and this got clogged up with traffic. There is a pinch point on this 'A' road at Starcross where two pillars forming part of a property jut out into the carriageway so it's single file only there and it sounds as if this created a lot of trouble.
  • All sorts of suggestions from the public and others about how to avoid similar problems in the future. One was to cone off an uphill lane on Haldon and Telegraph Hills when snow is forecast so that gritting lorries etc can get through without hindrance.
  • From what I heard today it looks as if underoad heating is being looked at. Nice idea but surely a non-starter. Yes I know that there are heating elements in the Hammersmith Flyover but I'm sure that was all part of the design. I don't know anything about the newest technology but the area at Haldon would be huge and the disruption massive. I really can't see that one flying.
  • Similar problems occurred at Telegraph and Haldon Hills less than 12 months ago, in February 2009. On that occasion the sudden snowfall was well into the evening , after I think most commuters would have been home.
  • I have memories from decades back of getting stuck on Haldon. It was in the morning I think and I believe it was a similar case of waiting patiently for gritting lorries to clear a way through. Much less traffic back then and I don't recall having to wait for hours for it to be sorted out.
  • Another morning memory is of going up Telegraph Hill in daylight but with snow on the ground in what was known as a "sit up and beg" Ford Popular of 1950's vintage. Side valve engine, three speed gearbox and 6 volt battery sums it up. But successful in the snow. It had tall wheels, excellent ground clearance and with very little power wheel spin didn't appear to be a big problem! I might have been more confident at the time as well of course.
  • Although the Haldon area grabbed the headlines on Tuesday there were other parts of Devon and Cornwall where drivers became stuck. Particularly badly hit were the A386 between Tavistock and Okehampton and, west of the Tamar, the Liskeard area.
As I stated at the start of the piece so local is the weather that we experienced none of that particular bout of mayhem here. As ever the elements can make man look very puny indeed.

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