Grimsvotn volcanic ash cloud threatens Scottish, Irish air space (VIDEO)

Ash from the erupting Icelandic volcano Grimsvotn was approaching Scotland and Ireland and set to disrupt flights there as early as Monday night, according to Britain's Met Office.

The plume from Grimsvotn, about 120 miles east of Reykjavik, which erupted late Saturday, has already disrupted airspace over Iceland and Greenland and disrupted some Scandinavian trans-Atlantic flights. Iceland's main airport remained closed Monday morning, after being shut down late Saturday.

Britain's Civil Aviation Authority (CAA) spokesman Jonathan Nicholson said authorities had no plans to close airspace — rather, they would give airlines information about the location and density of ash clouds and any airline that wanted to fly would simply need to present a safety report to aviation authorities, the Associated Press reports.

That in contrast to the approach taken last year, when Eyjafjallajokull erupted and European aviation authorities closed large swathes of European airspace for five days, grounding thousands of flights, stranding millions of passengers and costing airlines millions of dollars.

At the time, many airlines said authorities overestimated the danger to planes from the abrasive ash, and overreacted by ordering the biggest airspace shut down since World War II.

Nicholson said most British airlines had permission to fly through medium density ash clouds, but none had asked for permission to fly through high density clouds, classified as having over 4,000 micrograms of ash per cubic meter.

Dutch airline KLM canceled at least 16 flights Tuesday according to AFP, while Loganair canceled 36, the Telegraph reports. 

The coasts of Scotland and Ireland were set to be hit by the smaller of two plumes from Grimsvotn, which had risen as high as 7.5 miles. However, a European Union spokeswoman said the ash cloud was "far from where we were a year ago."

Teitur Arason, an Icelandic meteorological office forecaster, said wind conditions were spreading the ashes in separate directions. "The winds high in the air, above 25,000 feet or thereabout, are southeasterly, so that ash is blown to the north and then later to the east," he said, Al Jazeera reports. "But at lower levels, the winds are northerly and therefore those ashes are blowing southward."

The ash plume was also unlikely to affect the travels of President Barack Obama, who arrived in Ireland on Monday, as most flight paths in and out of Ireland ran far south of the ash cloud's projected path.

An Icelandic meteorological official said the eruption already appeared to be getting smaller, but Thierry Mariani, France's transport minister, said it was too early to tell whether air travel over Europe would be affected by the eruption, according to the AP.