5 Fascinating Facts About Icebergs

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Only 10% Is Visible Above Water

Ice is only slightly less dense than water, so it floats — but about 90% of an iceberg's volume stays hidden below the surface. That's where the expression "tip of the iceberg" comes from.

The Phenomenon of "Calving"

When a massive chunk of ice breaks off from a glacier or ice shelf and drifts into the sea, the process is called "calving" — and the piece that breaks off becomes an iceberg.

Its Role in the Sinking of the Titanic

The iceberg the Titanic struck in 1912 is believed to have broken off from Greenland in the Arctic and drifted into the Atlantic. The disaster led directly to the creation of international iceberg-monitoring patrols.

It's Actually a Block of Fresh Water

An iceberg isn't frozen seawater — it forms from snow compacted over long periods into freshwater ice, which then breaks off a glacier. That means when it melts, the water is drinkable.

Why Some Appear Blue

Ice compressed over a long time loses nearly all its trapped air bubbles, which causes it to absorb light at the red end of the spectrum and reflect blue light, giving some icebergs a mysterious blue tint.

Where the Phrase "Tip of the Iceberg" Comes From

This widely used expression, meaning that what's visible is only a small fraction of the whole, comes directly from the fact that most of an actual iceberg's volume is hidden underwater. It's often used to suggest that the hidden part of a problem or situation is far larger than what shows on the surface.

Frequently Asked Questions

Is it true that icebergs aren't salty?

Yes — since icebergs are freshwater ice formed from compacted snow, they contain almost no salt, and polar explorers have even used them as an emergency source of drinking water.

How does climate change affect icebergs?

As global warming accelerates glacier melt, calving events are happening more frequently, which is cited as one of the major contributors to rising sea levels.