Geophysicist Páll Einarsson has sent a letter to the Icelandic Transport Authority in which he points out that it can be risky to fly over Hekla volcano in South Iceland as it may erupt with little notice, causing pilots to fly into the ash plume with disastrous consequences.
A pilot almost flew into the ash plume of Hekla when the volcano started to erupt on August 17, 1980, as reported on mbl.is.
The website alltumflug.is studied how many airplanes flew over the volcano on Thursday and found that they were 19, 17 passenger jets, one private jet and one cargo plane.
Páll reasoned that his concerns don’t have anything to do with the usual risk of flying across an active volcano; there are approximately 30 volcanoes in Iceland and most of them pose little danger to aviation safety, he said.
Hekla is unusual for three reasons, Páll stated. The aviation route across the volcano appears to be rather popular among pilots, Hekla has been preparing to erupt since the last eruption ended in 2000 and the notice when Hekla erupts is particularly short, 23-79 minutes.
Páll believes there may be too little time to issue a warning to pilots if Hekla would start to erupt. Traditionally, the start of an eruption in Hekla is powerful with the ash plume rising fast; it would only take it five to 20 minutes to reach the altitude of airplanes.
To be safe, Páll recommends moving the aviation route 10 km (6 miles) to the north or south of Hekla. He added that the same risk does not apply to eruptions in Vatnajökull glacier, because, as in the case of Bárðarbunga, it would take the magma several hours to break through the ice.
The Icelandic Transport Authority responded that no limitations are made to air traffic unless an imminent eruption is foreseen or an eruption has already begun.