The ash plume from the 2010 Eyjafjallajökull eruption.
To say that the Eyjafjallajökull eruption has become the most significant volcano-related news story of the year would be an understatement. There has been wall-to-wall coverage on every major media outlet, dissecting everything from the effect of ash on jets, to the effect of ash on people, to wildly premature commentary on the climatic effect of the eruption to the potential place in history of this event. The eruption is affecting a wide swath through society: the European economy may take a hit of billions of dollars due to cancelled flights, the funeral for the late Polish president may be delayed, bands heading from Europe to the Coachella festival are having to cancel, and much much (much) more. However, the airspace from Iceland to Russia and as far south as Germany is still closed, with really no end in sight at this moment (although some airlines are trying limited flights).
Now, based on the discussions here on Eruptions and my conversations with people, I would say none of us guessed that the ash hazard from Eyjafjallajökull was going to be this distruptive to air travel in Europe. Most of the discussion was short term events -floods, lahars in Iceland - or long term - climate effects due to the released aerosols. This goes to show how significant the threat of ash is to aircraft and how globally disruptive it can be. If you need an example of how this might affect the United States, imagine the disruption to air travel if Mt. Rainier were to have an ash-laden plinian eruption.
The eruption itself seems to be continuing strong - and by some reports, intensifying. The latest update from the Icelandic Met Office reads:
The plume from the eruption in Eyjafjallajökull volcano is still ongoing, reaching hights of 4 to 5 kilometers, occasionally reaching higher altitudes. The plume drifts with north-westerly winds reaching Europe. It has been detected over Norway, Sweden, northwestern Russia, northern Polland, northern Germany, northern France and southern UK. There is no indication that the ash from the volcano is decreasing and it is predicted that high-level winds will stay north-westerly today.
Not exactly what weary travelers around the world want to hear right now.
Lahar from Gígjökull glacier, taken April 16, 2010.
Mudflows (lahars) and floods caused by the rapid melting of the Eyjafjallajökull ice cap are still a dangerous hazard to people near the volcano in Iceland - you can see some of the mudflow deposits (Icelandic) on the Icelandic Met Office website (and above), typically looking like thick, grey flows likely full of volcanic ash and tephra. We are beginning to get some idea of the aerosol emissions from the volcano as well - with sulfur dioxide plumes and fluorine (Icelandic)concentrations. Again, I warn against drawing any conclusions about climate from this eruption at this point! Remember, all the volcanoes in the world release 130 times less CO2 than the human race does each year, so even big eruptions add relatively little to the atmosphere. You can still watch the eruption through the clouds on both the Vodafon and Mila.is webcams.
The far-reaching effects of the ash are evident everywhere, especially from space. The ash has fallen on the British Isles and the threat of ash looks like it could be here for a while. Important to keep in mind, if you are concerned about the ash hazard, please check out the USGS page on ash - it does an excellent job of explaining the hazard posed by ash and what you can do to protect yourself and your property.
There is so much news about this eruption being put out that I will try to update this post throughout the day as I find more interesting information about the eruption.
UPDATE 1: More an update on people than the volcano, but I just found out that Einar Kjartansson of the Icelandic Meteorological Office, one of the key spokesmen on the eruption is a Denison University alum (where I currently teach). Go figure!
UPDATE 2: Eruptions reader Hanns posted new compositional analysis of the ash from the explosive eruption. Most is ~57-58 wt% silica, which makes it andesitic overall. This is a change from the basaltic magma of the earlier fissure vent eruptions. The question is whether the change means that the basaltic magma is mixing and/or assimilation the rhyolitic crystal mush in the Eyjafjallajökull volcanic edifice, or something else is being tapped. The ash is fairly Ti and Fe rich as well, which might suggest a large component of the more primitive basalts from earlier in the eruption. Now we just need to get a hold of an actual chunk of the tephra to see the textures!
UPDATE 3: Curious how much this ash is costing airlines? The latest estimate is $200 millions a day!