For the time being at least, airlines and their passengers appear to have avoided a full-blown rerun of last year’s volcanic ash crisis. Despite the fact that the May 21 eruption of Iceland’s Grímsvötn volcano spewed more ash into the air during the first 24 hours than the infamous Eyjafjallajökull had done throughout April and May in 2010, flight operations in Europe essentially returned to normal by May 26.
As of 10 a.m. on May 26, Eurocontrol forecast “little or no impact on European air traffic in the coming 48 hours” despite lingering concentrations of ash. Between May 23 and the end of May 25, operators canceled almost 900 flights out of approximately 90,000 planned movements. Most of the cancellations resulted from airport closures in Scotland and the north of England on May 24. German airports at Bremen, Hamburg and Berlin closed on May 25.
While Grímsvötn did generate large volumes of ash, stronger winds and different weather patterns meant the material dispersed more quickly and did not linger as long in busy airspace as it did during Eyjafjallajökull’s eruption last year.
At the same time, aviation authorities in Europe–most notably in the UK–showed a greater resolve to resume flights based on new parameters developed since 2010 for assessing actual threat levels posed by volcanic ash. Airlines can now make a case–based on technical data specific to their aircraft and engines–for operating in medium-density ash clouds (containing between 2 and 4 grams of ash per 10 cubic meters of air).