Glacier, bedrock and meltwater. Glaciers are rivers of ice that form when compacted snow from high ground turns into ice and flows downhill under its own weight. The weight of the ice as it moves forward erodes the underlying bedrock, and creates ground up rock under and around the glacier. This debris (such as the brown smears at left) is known as moraine. The underside of a glacier is also where some of the melting occurs, and here a meltwater waterfall (lower centre) is seen emerging from under the glacier. This is the Conwaybreen Glacier in Svalbard, an Arctic archipelago governed by Norway.