What are icebergs?

What are icebergs?

How can ice be dangerous?

Icebergs look like huge frozen mountains, floating low in the water. They are an impressive sight, but are dangerous things for a ship to encounter.

How do icebergs form?

Glaciers, slow moving rivers of ice, flow over land in Antarctica and the Arctic. When the edge of a glacier meets a sea or ocean, it forms an ice shelf. The edge of the glacier floats on water.

An iceberg forms when part of the ice shelf cracks and breaks off. The iceberg is free to float into the ocean and drift away from the land.

How big are icebergs?

Icebergs come in all shapes and sizes, from the size of a car to the size of a US state!

The tip of an iceberg can be over 50 metres above the surface of the water. The smallest types of icebergs are known as growlers, the size of a car, and bergy bits, the size of a house.

The biggest iceberg ever seen was nearly the size of Connecticut - 6,500 square kilometres!

Why are icebergs dangerous?

Sometimes icebergs flip over, causing huge amounts of energy to be released.

Scientists at the University of Chicago calculated that a rolling iceberg may release as much energy as an atomic bomb.

When an iceberg flips, it can cause tsunamis and may even trigger an earthquake.

The most famous iceberg is probably the one which sank the Titanic. Titanic was called the "unsinkable ship. Sadly, an iceberg hit the side of the Titanic, creating a huge hole in the ship's side. Water flooded in and the Titanic sunk. Over 1,500 people died.


Ship dwarfed by iceberg

How do we spot icebergs?

After the Titanic disaster, an international agreement led to the formation of the International Ice Patrol (IIP).

The Ice Patrol watches over Iceberg Alley, the area off the coast of Newfoundland near to where the Titanic went down. It's an important route for ships.

International Ice Patrol

International Ice Patrol watch over Iceberg Alley

The IIP uses aeroplanes to find icebergs and collect ships' reports about icebergs. The information is fed into a computer that uses tracking models and information about ocean currents to estimate where icebergs will float to and when they'll get there. This information is sent via the internet and radio to nearby ships. It saves lives from another iceberg disaster.

The IIP have tried to track icebergs and make them more visible. One idea was to spray icebergs pink, but it washed off as the iceberg flipped over! They even tried dropping bombs on them. This just caused large icebergs to break up into smaller icebergs, which can be just as dangerous. So far, the best method for tracking icebergs is using aeroplanes and ship reports.