Erosion Path (view up hill towards the summit) Image 1 of 2
This image was taken during a geology field study course I took. Even our professor was surprised at the amount of damage that we witnessed here and mentioned that there were a number of camping sites wiped out further below.
As for the cause we concluded it was started by a glacial outburst flood (also called by the Icelandic term "jokulhlaup") due to heavy rains and snow/ice melt in the early part of the year. An accumulation of water builds up behind an ice wall (foot of a glacier for example) and eventually the force of the water causes the ice wall to yield and the water bursts through it. The large volume of escaping water causes heavy erosion to the surrounding surfaces and gathers up large amounts of sediment and debris along the way. The image shows mostly volcanic rock deposition which indicates this area was close to the source of the flow and just below the tree-line, otherwise mud and vegetation evidence would also be visible.