During their seagoing careers, most mariners will never see ice and even fewer will have to navigate through it. In all its forms, whether land-generated or ocean-created, ice afloatis a fascinating sight in terms of colors, forms, and creation.
Land-based freshwater ice enters the oceans through the calving of glaciers at the point where they meet the sea, creating typical craggy icebergs. Ice shelves that flow from land over the ocean are another major source. Unlike glaciers, these ice sheets float on the ocean surface and can be massive. For example, the Antarctic's Ross Ice Shelf is the size of France. As the outer edges break off, huge tabular floes are created; some of them can be the size of small states or nations.