What Color Is an Iceberg?


Icelandic Blue Striped Iceberg
This iceberg is blue from glacial ice, with black stripes from volcanic ash. (Anne Helmenstine)

Most icebergs are white, but they occur in a wide range of colors, including blue, green, yellow, black, and striped. The colors depend on the amount of air in the ice and whether it contains any impurities. Iceberg color changes over time. Exposure to air and sunlight can erode the iceberg surface, causing it to scatter more light and appear whiter. As the iceberg moves through water, it can roll, exposing a smoother, darker surface.

Why Most Icebergs Are White

Icebergs are usually white that is tinged with blue because they are made of frozen fresh water. They are chunks broken off of glaciers, which form when snow gets compacted until it fuses into ice. Over hundreds of years, pressure forces all air out of the ice, leaving few reflective surfaces. Long wavelength light (e.g., red) is absorbed, so the ice appears blue or blue-green. An ice cube appears clear or white, but a large volume of ice (or liquid water) is blue. Icebergs typically appear white because their surfaces may be coated with snow or else weathered so they reflect light.

This smaller iceberg or growler is black because the ice is very pure. When removed from the water, it would appear clear. (Kim Hansen)
This smaller iceberg or growler is black because the ice is very pure. When removed from the water, it would appear clear. (Kim Hansen)

How Iceberg Colors Work

Glacial ice appears blue or white, so how do icebergs get other colors? Usually, these colors come from impurities in the ice:

  • Yellow: Dead plankton in seawater can freeze onto icebergs. Mineral particulates, particularly from iron oxides, can run off soil into water and freeze, adding a golden, brown, or red color. The water itself is fresh water, but it contains particulates that shift the color of the ice.
  • Green: If you mix the blue of the iceberg with yellow from organic matter, you can get a green iceberg. Mineral particles in the water also produce green.
  • Black: There are two ways black icebergs form. First, if the ice is very pure and free of air bubbles, it can absorb enough light to appear black. Small pieces of this ice appear perfectly clear. Other black icebergs form when volcanic ash is deposited upon a glacier.
  • Stripes: Colored stripes can appear when parts of the glacier melt and re-freeze or when seawater floods cracks and freezes. If the water is pure, the stripes are blue, aqua, or translucent black. If the water mixed with minerals or organics from soil or seawater, really any color of stripe might result. Opaque stripes can result from movement of the glacier over land. Near volcanic areas, black stripes result from ash deposited by volcanoes.
Black Iceberg
This Icelandic iceberg contains a lot of black from volcanic ash. (Anne Helmenstine)

Where to See Icebergs

You don’t have to travel to Antarctica to see icebergs.

In the northern hemisphere, one great iceberg viewing location is “Iceberg Alley” off the coast of Newfoundland, Canada. The icebergs calved from Greenland glaciers before traveling across the Atlantic to Newfoundland and Labrador. So naturally, Greenland has icebergs. Iceland also has icebergs. The Icelandic icebergs are at Jökulsárlón, which is a lagoon containing icebergs calved from the Vatnajökull Glacier. The icebergs are easily viewed from the shore of the lagoon, or you can take a zodiac or amphibious boat tour to see them up-close. Ice from Jökulsárlón makes its way to a black volcanic sand beach, called Diamond Beach because the sparkling bits of ice resemble gems. The Knik Glacier in Alaska calves icebergs into its own glacial lake, but you’ll need to take a ride in a small airboat to reach it.

In the southern hemisphere, visit Torres del Paine National Park in Chile where Gray Glacier calves into a lake. Alberto de Agostini National Park is another iceberg viewing location in Chile. This park is remote and requires taking a long (and expensive) boat trip. New Zealand also has icebergs. While the Tasman Lake doesn’t have quite as many icebergs as some of the other locations, it’s easy to reach by car in Mount Cook National Park. You can even kayak around the icebergs.

The world’s icebergs are tracked. Icebergfinder.com maintains a map and photos of icebergs traveling between Greenland and Canada. The USGS has a map showing typical iceberg distribution around the North Atlantic and Antarctica.

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