The winter of 2009-2010 in the United Kingdom (also called The Big Freeze by British media) was a meteorological event that started on 16 December 2009, as part of the severe winter weather in Europe. Temperatures in December were half the average for that month in the UK. January 2010 was provisionally the coldest January since 1987.
The winter weather brought widespread transport disruption, school closures, power failures, caused sporting events to be postponed and 25 deaths.
In most winters, and certainly those in the last 20 years or so, our winds normally come from the south-west. This means air travels over the relatively warm Atlantic and we get mild conditions in the UK. However, this winter Atlantic air has been ‘blocked’ and cold air has been flowing down from the Arctic or the cold winter landmass of Europe.
The cold temperatures in the UK have also been accompanied by snow. This is because areas of low pressure have been running in from the north-east, tracking across the North Sea and picking up moisture along the way. When they come over the land, the water falls as snow due to the cold temperatures.
The situation this winter is known as an "Omega block" as it consists of two high-pressure systems which on a weather map resemble the two arms of the Greek letter Omega – the Greenland one, and the Siberian anti-cyclone itself (whose stillness and clear skies are causing its intense cold, as much as 48C below zero in some places).
So if it is the longest cold snap for 30 years, does that prove that the idea of global warming is a non-starter? Funnily enough, it doesn't. For once you look at current meteorological conditions across the whole world, a different picture emerges.
It is colder than usual in some parts of the northern hemisphere, and warmer than usual in others. Alaska and northern Canada are 5-10C warmer than the average for this time of year, so are North Africa and the Mediterranean. The cold and the warmth could be related: the contrasting temperatures appear to be connected to blocks of high pressure preventing air flow between the land and the sea.
Mild weather is expected to see out what remains of winter. Despite this, it is expected to be the coldest UK winter since 1995/96, according to provisional Met Office figures.
The low temperatures have also been accompanied at times by heavy snow. During early February, the heaviest snowfall for 18 years was experienced over many areas of the UK.
Mean temperatures (in degrees Celsius) across the UK.
| Mean temperature 1/12/2008 to 23/02/2009 | Average winter
temperature (1971 to 2000) |
December to February 2007/8 | December to February 1995/96 | |
|---|---|---|---|---|
| UK | 2.9 °C | 3.7 °C | 4.9 °C | 2.5 °C |
| England | 3.2 °C | 4.1 °C | 5.5 °C | 2.8 °C |
| Northern Ireland | 3.7 °C | 4.3 °C | 5.5 °C | 3.7 °C |
| Scotland | 2.3 °C | 2.7 °C | 3.6 °C | 1.8 °C |
| Wales | 3.2 °C | 4.2 °C | 5.5 °C | 2.8 °C |
Some low night time minimum temperatures from across the UK were also recorded this winter.
| Location | Temperature |
|---|---|
| Aviemore, Highland | -18.4 °C |
| Benson, Oxfordshire | -11.8 °C |
| Shap Fell, Cumbria | -11.3 °C |
| South Farnborough, Hampshire | -10.8 °C |
| Sennybridge, Powys | -10.4 °C |
| Pembrey Sands, Carmarthenshire | -10.4 °C |
| Yeovilton, Somerset | -9.7 °C |
| Woodford, Greater Manchester | -9.6 °C |
| Culdrose, Cornwall | -7.8 °C |
Although cold, this year's low temperatures are put into context when compared to the all-time minimum figures for the UK nations.
| Lowest daily temperature records | |||
|---|---|---|---|
| Scotland | -27.2 °C | 11 February 1895 10 January 1982 30 December 1995 |
Braemar (Aberdeenshire) Braemar (Aberdeenshire) Altnaharra (Highland) |
| England | -26.1 °C | 10 January 1982 | Newport (Shropshire) |
| Wales | -23.3 °C | 21 January 1940 | Rhayader (Powys) |
| Northern Ireland | -17.5 °C | 1 January 1979 | Magherally (County Down) |
Scientists point out that the people must distinguish between climate and weather. Weather is what happens in the short term whereas climate is the long term trend.
Weather is caused by disturbances within the atmosphere, mostly in the lowest 10-15km of it, but climate is controlled by external influences, such as latitude, the distribution of oceans and continents, the position of mountain ranges, the distribution of ice and snow-cover, variations in the amount of energy emitted by the sun, changes in the chemical composition of the atmosphere ,and changes in land-use. Climate is the underlying average, or if the climate is changing it is the underlying trend, whereas weather is the noise in the system.
Despite
the extreme weather
this winter, scientists say that the current cold snap does not
mean that climate change is going into reverse. In fact, the surprise
with which we have greeted the extreme conditions only reinforces how
our climate has changed over the years.
In the UK, 2009 as a whole was the 14th-warmest on record (since 1914). This above-average temperature trend was reflected globally, with 2009 being the fifth-warmest year on the global record (since 1850).
The current cold weather in the UK is part of the normal regional variations that take place in the winter season. It doesn’t tell us anything about climate change, which has to be looked at in a global context and over longer periods of time.
The weather's natural variability means it is impossible to draw long-term conclusions about a changing climate from any single episode, be it of hot, or cold.
The cold weather the UK has experienced this winter has been in contrast to the run of very mild winter temperatures that have been recorded over recent years.
Natural variability of climate means that the UK will continue to see spells of colder weather at times. Although, if it had not been for the general warming already observed in global temperatures, this winter may well have been even colder.
Peter Stott, Climate Scientist at the Met Office, said: "Despite the cold winter this year, the trend to milder and wetter winters is expected to continue, with snow and frost becoming less of a feature in the future.
"The famously cold winter of 1962/63 is now expected to occur about once every 1,000 years or more, compared with approximately every 100 to 200 years before 1850."
We have always had huge day-to-day and year-to-year variations in our weather, and we always will do, and a single cold winter is no more evidence that climate change has stopped than a single summer heat-wave proves that global warming is happening.
Britain has had its deep-frozen winters in the last 100 years – 1940, 1947, 1963 and 1979 among them.
We are still some way off the coldest winter in living memory, the great freeze of 1962-63. That winter turned so cold that the sea froze around the South Coast, icebreakers were used to keep ports open and ice floes floated down the Channel.
Several trains were abandoned in snowdrifts, and buses stopped working when their fuel froze. On January 22 a car drove across the frozen Thames at Oxford, and even Central London was snowed under with a 4.6m (15ft) snowdrift at Oxford Circus. Over the winter 49 people died outdoors from the cold, many trapped in cars during blizzards. It was reckoned to be the coldest winter since 1740.
Meteorologically, winter is regarded as the months of December, January and February. The Met Office forecast is that mild weather is expected to see out what remains of winter.
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