The Icelandic Met Office in mid-August raised its aviation alert level to ‘orange’ as a result of activity in the Bardarbunga volcano, following a major earthquake, the largest in the area since 1996. On the five-color scale, orange sits one level below red, which denotes an active eruption, or one that is imminent. The 25km-wide volcano sits beneath Europe’s largest glacier and rises about 1,890 metres sea level. 

The warning will ensure that airlines flying across the Atlantic monitor the situation; some are likely to alter course between Europe and North America, given the risks. In April 2010, the Eyjafjallajökull volcano erupted causing massive flight disruptions across Europe. More than 100,000 flights were canceled, affecting about 10 million people with the disruptions overall costing an estimated US$2 billion.