Iceland Stands Down On Travel Alert: From Orange To Red and Back Again

Iceland's tiered system of air travel alerts went to orange last week, then to red with a believed under-ice eruption of the volcano beneath the Dyngjujokull glacier, but has now been eased back to orange. "Observations show that a sub-glacial eruption did not occur yesterday. The intense low-frequency seismic signal observed yesterday has therefore other explanations," the Icelandic Met Office said. The office had therefore decided to move the aviation warning code from red to orange, it said, but since there was no sign the seismic activity was slowing down, an eruption could still not be excluded. The national police commissioner said separately that all restrictions on aviation had been cancelled. Airspace of 140 by 100 nautical miles above the volcano had been closed to aircraft on Saturday.

Re:OMG

[Zocalo]

Probably just erring on the side of caution after Eyjafjallajökull in 2010. There are a whole number of ways the potential eruption, if it happens all, could go but most of them are probably not going to result in massive volumes of ash being pumped into the atmosphere; the most likely outcome being that the melting ice will cool the magma and prevent anything hazardous reaching the atmosphere. The main danger from Iceland's sub-glacial eruptions is actually the hlaup, or outflow of water from beneath the glacier in the form of a potentially devastating flash flood, which is why people have already been evacuated from the highlands. If there is an eruption, I suspect the priority with be evacuating whichever sections of the coastal lowlands are going to be in the path of any outflow (somewhere along the South coast, I suspect), rather than rerouting aircraft in the area.

Re:OMG

[Rei]

The real problem isn't the subglacial volcanoes, though. It's Hekla. They've been talking about this in the Icelandic press a bit, basically she usually gives an average of a couple dozen minutes advance warning, and then the ash plume reaches flight level in 5-20 minutes. Yet a dozen or so commercial passenger jets fly over her every day. There's one volcanologist recommending a permanent air traffic closure over her. The current situation really looks to be just asking or a serious tragedy at some point in the coming decades.