Freak diversion of jet stream propels freezing conditions
The freezing conditions that have blasted Britain are being blamed on a series of weather patterns that are bringing Arctic temperatures to much of western Europe, California and even Australia.world Updated: Dec 23, 2010 15:54 IST
The freezing conditions that have blasted Britain are being blamed on a series of weather patterns that are bringing Arctic temperatures to much of western Europe, California and even Australia.
One of the main factors is a change in the position of the jet stream - the fast-moving current of air that moves from west to east, high in the atmosphere.
Changes in the jet stream's path can cause massive changes in weather conditions across the globe and this may be why Australians are now shivering their way through summer and California is witnessing the current freezing conditions.
In a normal British winter - when conditions are mild and soggy - the jet stream lies over northern Europe, at an altitude of between 35,000 to 50,000 feet, TheDaily Mail reports.
During these grey winters, Britain's prevailing winds come from the west and south west, and bring with them warm and moist air from the sub-tropical Atlantic.
In 2010 a high-pressure weather system over the Atlantic is blocking the jet stream's normal path and forcing it to the north and south of Europe.
The areas of high pressure act like stones in a stream - blocking the normal flow of milder air from the west and instead forcing colder air from the north down across Britain.
In California, more than 12 inches of rain fell in parts of Santa Monica Mountains in the south and 13 feet of snow has accumulated at Mammoth Mountain ski resort.
And Australians expecting to bask in early summer sun this Christmas are instead shivering as icy gusts sweeping up from the Southern Ocean have blanketed parts of east coast states, New South Wales and Victoria with up to four inches of snow.
Other weather patterns that are also causing havoc across the globe, may be affecting the weather too, such as the current in the tropical Pacific Ocean, called La Nina, which is disturbing the jet stream over the north Pacific and North America.