The Big Freeze

For many parts of our region the snow on the night of the 4th January was the heaviest snowfall in many years. Radio Gloucestershire weather historian Ian Thomas reckons it was the biggest January dump of the white stuff since 1987.

It comes shortly after the Met Office issued a more pessimistic forecast for the remainder of the winter – hardly surprising when you look at the upper air patterns across the Northern hemisphere. The blocking anticyclone has cut off our usual supply of mild, wet Atlantic air and instead left us open to icy blasts which originate from within the Arctic Circle.

        At times even the Floating Harbour has frozen over (Picture: Justin Myers)

The extent of the cold air across Europe does suggest that the cold weather could persist for quite some time. Certainly there is no sign of any thaw within the next two weeks. Instead we could see some record low temperatures in parts of our region. This is a result of the combined effect of persistent cold weather and extensive snow cover. The snow has an insulating effect, trapping what little heat the ground usually releases. This allows the air to radiate its heat into the atmosphere.

In extreme cases temperatures in the West Country can fall as Minus 20 degrees in such conditions. On 14th January 1982 temperatures fell as low as Minus 16C at Yeovilton, Minus 19C at Filton and a bone chilling Minus 20C in Cheltenham. We probably won’t achieve anything quite that low but it could be a close run thing.

     The snow of 1982 in Rodbourne Road, Swindon (Picture: Dave Wallis)

It could be argued that when it is very cold then a few degrees here and there do not matter much. But when temperatures drop below Minus 7C salt applied to road surfaces becomes much less effective. Fortunately this phenomenon is a rare occurance, but because of that it often catches drivers unaware and even salted roads (we talk about ‘gritters’ but they generally only use pure salt) can become very icy.

All this of course is seen as grist to the mill for the climate change naysayers who like to pretend there is no difference between weather and climate. But even 50 years from now it is likely we will occasionally have to battle against some of the worst that Mother Nature can throw at us.