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
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.