Before the photo, some geology:
A “skriðjökull” (literally “crawling glacier” in English) is the Icelandic name for outlet glaciers, the tongues of ice protruding from ice caps in which you can see the constant movement and flow of the ice in the whorls and cracks on the surface. They crawl down valleys that they have carved over the millennia and generally have rivers running from under them and some have glacial lagoons in front of them where the river has been dammed by glacial drift: rocks and rubble that the tip of the flow churned up before the glacier began receding. Many of them have names distinct from the ice caps they originate in.
The following photo and the photos I’ll post in the next couple of days are from a visit to Gígjökull (“Crater Glacier”), an outlet of the infamous Eyjafjallajökull. It once had a lagoon in front of it (here’s an aerial photo), which got wiped out in the April 2010 eruption of Eyjafjallajökull when a massive flood burst from under the glacier and washed away the natural dam (here’s a video, (it has an ad in front). Now there is just the river, and the foot of the glacier is considerably smaller and more tongue-shaped than it was before the flood. The deep fissure to the right of the glacier itself is where the main body of the flood came down.