Return of the ash

Monday 23rd May 2011 by theWeather Club

Almost a year to the day after the eruption of the Eyjafjallajokull floored Britain's flights and baffled its newsreaders, another volcanic eruption in Iceland has started spewing troublesome ash into the atmosphere.

The slightly more pronounceable Grimsvötn volcano, located in the south east of the country, has been erupting since Saturday in what volanologists have said is its largest eruption in 100 years. Yet while Icelandic air traffic control has imposed a no-fly zone in the immediate vicinity and cancelled all domestic flights, a spokesman for the UK's Met Office has reassured the BBC that "this is a very different situation to last April".

"The weather is much more changeable and there's a lot more uncertainty. There's no risk of the ash moving across the UK in the next day or so," said the Met Office, which is are responsible for running Europe's Volcanic Ash Advisory Centre. However, it did not rule out the possibility of seeing some volcanic ash "towards the end of the week".

In the meantime, authorities say they are carefully monitoring the size of the ash particles and the prevailing weather patterns, both of which played an instrumental role in last year's six day long disruption.

"That was an unusual volcano, an unusual ash size distribution and unusual weather pattern, which all conspired together to make life difficult in Europe," University of Iceland geophysicist Pall Einarsson told the BBC.

At the moment, it is thought that if the volcano continues to erupt at the same intensity, the ash cloud could reach the west of the UK on Thursday or Friday. However, the prevailing low pressure system hovering above us means the Met Office's confidence in these predictions is still low.

Even if the cloud does reach our airspace, differences in ash size, better-equipped aircraft (which can land in low density clouds) and a continuously changing wind system mean it is "likely to be less than in the 2010 Eyjafjallajökull eruption", said Open University volcanologist Dr Dave McGarvie, who also pointed out that the last two times Grimsvötn erupted it did not affect UK air travel.