Iceland Stands Down On Travel Alert: From Orange To Red and Back Again 29
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 (Score:5, Insightful)
Anyway I don't know why they had an alert - surely it would take many hours for the lava to burn through the ice, so ther would be plenty of time to divert planes before it went boom and blocked the flight path with ash.
It's probably better to set flight plans before take-off and not change them at the last possible moment except in the event of a unpredictable emergency. You don't want to be one radio failure away from an engine full of ash.
Re:OMG (Score:4, Insightful)
Iceland's volcanoes have indeed done that quite a few times. Eruptions connected with Laki in particular have been nasty, the 970 eruption was reported to have frozen the Tigris and Euphrates in central Iraq, and the 1783-1784 eruption froze the Mississippi at New Orleans and there was ice seen floating in the Gulf of Mexico. Which is even more impressive when you realize that the closer a volcano is to the poles, the harder it is to alter climate suchly; Iceland's volcanoes give off abnormally high levels of SO2 (also, really unfortunately from a local perspective, HF). Laki's 1783-1784 eruption, for example, gave off a whopping 120 million tonnes of SO2 and 6 million of HF, 6 times more SO2 and orders of magnitude more HF than Pinatubo, the largest eruption of the 20th century.
The problem with that, however, is that these effects are only short term. Meanwhile, volcanoes also give off CO2, which contributes to warming and last much longer. So they provide short-term cooling but long-term warming.