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Ash cloud to move to Arctic

2010-04-20 15:18

Geneva - The volcanic ash cloud from Iceland is expected to change directions and head towards the Arctic when the weather changes towards the end of the week, the World Meteorological Organisation said on Tuesday.

"The current high pressure system with weak winds and slowly descending air in the centre of the high does not help very much to disperse the ash cloud," the UN weather agency said in a factsheet.

"This situation is expected to change towards the end of the week, when a stronger low pressure system over Iceland is predicted to develop."

"Not only will such a low change the winds and push the ash towards the Arctic, but the rains associated with this low pressure system will result in a degree of 'wash out' of ash at lower levels," it added.

Ash descending

For the moment, the cloud of very fine ash is expected to remain "for quite some time" in the atmosphere while they await thunderstorms to wash them away, explained the WMO.

But some of the ash is descending, said the WMO, pointing to measurements which indicate that ash particles are now between ground level and 3 000m.

There is still evidence however that the cloud remains at higher levels.

The WMO also said that it has been informed on Tuesday that the Eyjafjallajokull volcano in southern Iceland is now spewing less ash, with the plume reaching "less than 3 000m".

"The whiteness of the plume furthermore suggested that it contains mainly steam and little ash," it added.

Initially, the volcano was spewing ash at heights of 9 000m.

The spread of the ash cloud brought about air travel chaos in Europe as authorities shut down their airspace over fears that commercial aircraft could be damaged by the fine ash particles.