Hidden blue beauty: Why glaciers and icebergs are blue underneath
Snow and ice are generally white, so why do we see a brilliant blue hue underneath an iceberg or on the edge of a glacier?
Visitors in Los Glaciares National Park, Argentina, were awestruck when they witnessed this rotating iceberg rolling toward them on Dec. 8, 2024.
A recent video of an iceberg in Los Glaciares National Park in December shows the ice slowly flipping in the water until a bright blue color is revealed. The stunning video prompted many who viewed it to ask what causes icebergs to turn from white to that vibrant color?
Color is created by light reflecting off an object. Color literally doesn't exist in the dark. It's not that you can't see it, it's that it's simply not there. We see an object in the colors that are reflected back to us, not the ones that are absorbed.
Snow appears white because there is a lot of air trapped in bubbles among the snowflakes, and these air bubbles reflect all colors. The same is not true around the edges of a glacier or iceberg, where brilliant blues can be seen.
This video of the Viedma Glacier in the Argentinian Patagonia was shot in March 2016. The glacier took about two hours to collapse and, according to tour guides, is the best ice calving they had seen in several years.
Glacier calving, also known as ice calving or iceberg calving, is a jaw-dropping natural event where massive chunks of ice break off from the edge of a glacier. This spectacular phenomenon occurs when the forward motion of a glacier destabilizes its end, causing huge pieces of ice to plunge into the water below.
An aerial view of Svalbard and surrounding glaciers during the 4th National Arctic Scientific Research Expedition on Arctic Ocean on July 21, 2024. (Photo by Sebnem Coskun/Anadolu via Getty Images)
Over time, new layers of ice and snow squeeze the air pockets out of the lower layers of glaciers and icebergs while creating a denser layer of ice crystals. During calving, when light hits this dense ice, it absorbs longer wavelengths of colors like red and yellow but reflects shorter wavelengths, like the dark blues you see in stunning videos of glaciers calving.
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