Viewing post #664460 by rannveig
|Well ..... here we go again.
A volcanic eruption started tonight in Grímsvötn an active volcano beneath our largest glacier Vatnajökull ....
Grímsvötn lake is one of the world's most active hotspots and has been very active in recent years. The last eruption was in 2004. Past eruptions this century have been relatively small and unproblematic, but this one is a HUGE. It's ten times more powerful than last year's eruption in Eyjafjallajökull, similar in size to a big Katla eruption which is what was the biggest worry last year. Fortunately Katla is still quiet.
There aren't many volcanos in the world located beneath a glacier covered lake. The geothermal activity melts the ice and the water accumulates in the craters (there are two). When the water level reaches a certain point the lakes emty out (usually not both at the same time) causing a flooding in the glacier fed rivers Gígja and [url=http://en.wikipedia.org/wiki/Skei%C3%B0ar%C3%A1]Skeiðará[/rul]. The last flood was in November 2010 so the water level in the lakes was very low when the eruption started. The flood last fall was expected to trigger an eruption which has been expected for quite some time and there was an alert issued for a few days after the flood. So the eruption now is no surprise, however it came with very short warning ..... at 5 pm there were no indications of an imminent eruption that started about an hour and a half later.
This article from april 2010 gives a good picture of Iceland's volcanos: http://news.bbc.co.uk/2/hi/europe/8623239.stm
All domestic and international flights have been cancelled today. The international airport was closed at 8:30 am and most morning flights were able to depart before the airport closed. There will be no more flights to or from the country today and possibly tomorrow as well. It's highly unlikely that it will affect transatlantic airtraffic other than flights being rerouted north or south of the plume.
There is very heavy ashfall on the south east coast. The situation is similar to last year, pitch black darkness in the areas with the heaviest ashfall. Two towns are most heavily affected, Kirkjubæjarklaustur and Höfn. There has also been some ashfall in Vík that also experienced heavy ashfall in last year's eruption. The farms in the area are worst hit ... farmers are rounding up their animals that had ben let outside already and getting them inside the barns again. Rescue workers have been distributing masks and safety goggles in the area since last night. In the areas most affected the ashfall is too heavy for car travel and they've been making the rounds on specially equipped vehicles with special air filters. The situation is bad and we can only hope it'll be a short eruption.