This gives you some idea about the amount of ash that was spewed out in last years volcanic eruption in Grímsvötn (wich by the way was considerably less than in the big one in Eyjafjallajökull two years ago). At the roots of Vatnajökull glacier (on wich Grímsvötn is located) it hasn’t snowed as much as higher up on the glacier so there was more thawing. But here the ash had formed a sort of protective layer for the ice. So basically, this is how thick the ash was here after the eruption.
Wow.
