This is taken at the foot of the glacier Nigardsbreen, which is a branch of the Jostedalsbreen glacier. What you see here is the river of melting water flowing from the glacier. You might expect the water to be clear, but it carries a lot of silt hence the murky look. This is of course emphasized by the long exposure.
You can get quite close to the edge of the glacier, and even onto the glacier. There are guided tours, anything from a short walk for families or a days walk for the more ambitious. If you look closely you may spot two people on the far left close to the edge of the ice - just to give you a sense of scale.