A dense ash cloud from an Icelandic volcano blew into Scotland, western Norway and Denmark last night, causing airlines to cancel flights and raising fears of travel disruptions.
Norwegian airport operator Avinor said the ash from the Grimsvotn volcano disrupted traffic to and from Stavanger and Karmoey airports and was expected to spread to southern Norway today.
Danish authorities said they had closed the airspace under 6km in northwestern Denmark.
There is no airport in that area, but the ash is causing delays and some cancellations at Copenhagen airport.
Britain’s Civil Aviation Authority was expecting ash to reach Scottish airspace late last night and to affect other parts of Britain and Ireland in the coming days.
Between 200 and 250 flights had been cancelled, said Brian Flynn, head of network operations at Eurocontrol, the European air traffic agency.
And he warned that up to 500 flights could be affected.
British Airways suspended all its flights for today between London and Scotland, and Dutch carrier KLM and Easyjet cancelled flights to and from Scotland and northern England at the same time.
The Irish Aviation Authority ordered all flights from Ireland to Scotland to be suspended.
Authorities say they don’t expect the kind of widespread grounding of flights that followed last year’s eruption of the Eyjafjallajokull volcano in Iceland because systems and procedures have been improved since then.
Experts also point out that the ash from the ongoing eruption appears coarser than the very fine ash from last year’s blast, and should therefore not travel as far.
CAA chief executive Andrew Haines said the first priority was ensuring the safety of people on board aircraft and on the ground.
“We can’t rule out disruption, but the new arrangements put in place since last year’s ash cloud mean the aviation sector is better prepared.”
Many airlines said authorities last year overestimated the danger to planes and overreacted by closing airspace for five days amid fears that the abrasive ash could cause engines to stall.
CAA spokesman Jonathan Nicholson said authorities would give airlines information about the location and density of ash clouds.
He 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, those classified as having over 4000 micrograms of ash per cubic metre.
Even at that concentration of volcanic ash, experts said, the air would not look much different from airspace unaffected by the ash, but officials say the tiny particles in the ash can sandblast windows and stop jet engines.
The international pilots’ federation warned that it believed the cloud was still a threat to commercial aircraft despite developments since last year.
Thurai Rahulan, a senior lecturer in aeronautics at Salford University in northwest England, said the technology on how to measure and monitor ash had improved, but aircraft’s ability to cope with ash had not changed.
Transport Secretary Phillip Hammond said Britain had equipment in Iceland analysing the ash.