the peak of the last ice age, one-third of the Earth's land
surface was covered by thick sheets of ice. Their high albedo
reflected a great deal of sunlight out into space, which cooled
Earth and allowed the ice
sheets to grow. (See our Ice
Ages web page.) Ice sheets give birth to icebergs. This
process is known as calving.
Most bergs are calved from ice sheets off the western coast of
Greenland and Antarctica. Icebergs are found in both the Arctic
and Antarctic regions. The bergs from these two areas differ,
however, in form and size.
what criteria must a chunk of ice meet to officially be called
an iceberg? By definition, icebergs are at least seventeen feet proud
of the water and fifty feet long. Anything smaller is called a growler
bits. One of the biggest Greenland bergs ever reported by
the Coast Guard was 550 feet above the sea. Icebergs in the
Arctic regions are formed from mountain glaciers
fed by the Greenland ice sheets and are high and narrow, with
above-water shapes resembling towers; these are called castle
bergs. Large tabular icebergs are found at the ice shelves
of Antarctica. One large tabular Antarctic iceberg in 1987 was
reported to be 100 miles long, 25 miles wide, and 750 feet
Iceberg is a floating mass of freshwater ice that has broken
from the seaward end of a glacier or a polar ice sheet. Icebergs
are typically found in open seas, especially around Greenland
form mostly during the spring and summer, when warmer weather
increases the rate of calving (separation) of icebergs at the
boundaries of the Greenland and Antarctic ice sheets and smaller
outlying glaciers. In the Northern Hemisphere, for example,
about 10,000 icebergs are produced each year from the West
Greenland glaciers, and an average of 375 flow south of
Newfoundland into the North Atlantic shipping lanes, where they
are a hazard to navigation.
icebergs vary in size from the size of a large piano, called
growlers, to the dimensions of a 10-story building. Icebergs
about the size of a small house are called bergy bits. Many
icebergs in the Arctic are about 45 meters tall and 180 meters
of the Antarctic not only are far more abundant but are of
enormous dimensions compared with those in the Arctic.
Ninety-three percent of the world's mass of icebergs is found
surrounding the Antarctic.
1/8th of an iceberg is above the waterline. That part consists
of snow, which is not very compact. The ice in the cold core is
very compact (and thus relatively heavy) and keeps 7/8ths of the
iceberg under water. The temperature in the core is constant:
between -15 and -20 degr. Centigrade. An iceberg that has
tumbled over several times, has lost is light snow layers and so
the iceberg gets relatively heavier then before (with the snow)
and because of the greater compactness, only 1/10th rises above
names are derived from the Antarctic quadrant in which they were
originally sighted. The quadrants are divided counter-clockwise
in the following manner:
A = 0-90W (Bellinghausen/Weddell Sea)
B = 90W-180 (Amundsen/Eastern Ross Sea)
C = 180-90E (Western Ross Sea/Wilkesland)
D = 90E-0 (Amery/Eastern Weddell Sea).
When an iceberg is first sighted, NIC documents its point of
origin. The letter of the quadrant, along with a sequential
number is assigned to the iceberg.
The National Ice Center is a tri-agency operational center
represented by the United States Navy (Department of Defense);
the National Oceanic and Atmospheric Administration Department
of Commerce); and the United States Coast Guard (Department of
Transportation). The National Ice Center mission is to provide
world-wide operational ice analyses for the armed forces of the
United States and allied nations, U.S. government agencies, and
the private sector.
come in different colors (but not different flavors). According
to Ian Dunlop, they come in white, light blue, or an aqua-green
type. White is the standard color and is a result of the ice and
snow covering the iceberg. Blue is also from the ice which has
compressed all the gas inside so much that the apparent color is
blue from light scattering, much like a blue sky. The aqua green
is from algae growing in the ice and is only seen when icebergs
roll over exposing the previously underwater sections to view.
are awesome! They are also dangerous, especially when they
journey into shipping lanes. It was just such an iceberg that
sank the RMS Titanic in April 1912. The Titanic was not the only
ship to ever hit an iceberg. It remains etched in our memory and
history because of the great loss of life. The recent
Oscar-winning film "Titanic" brought the tragedy to
the big screen. Humans touted that they had built an
"unsinkable" ship. Nature, however, proved them wrong.
The captain ignored the warnings of icebergs and proceeded at an
excessive speed with 2224 passengers on board. 1517 people were
killed as the ship came to a grinding halt upon striking the
iceberg and sank beneath the icy waters. It was this tragedy
that led to the formation of the International Ice Patrol now
maintained by the U.S. Coast Guard.
Coast Guard C130 airplane flying over a large iceberg
icebergs have attracted attention as a possible source of fresh
water. How do people in Arab countries get fresh water from an
iceberg? By lassoing the iceberg for harvest, of course. Towing
icebergs is not new. Icebergs are lassoed and towed away from
drilling rigs in the North Sea as a safety measure. A hundred
years ago ships used to haul small icebergs.
Alaskan company harvested icebergs floating in Alaskan waters
and sold the ice to a firm in Japan as a novelty. One major
problem is how to tow the iceberg from the Arctic to the
equatorial zone without it melting before reaching its
destination. Another problem is how to harvest the fresh water
from the iceberg once it arrives.
Icebergs are white, blue, or green and sometimes even black
due to rock materials that were first in the glacier and
ended in the sea because of the iceberg.
of Newfoundland and Labrador A majority of the
icebergs in the North Atlantic come from about 100 iceberg
producing glaciers along the Greenland coast while a few
originate in the Eastern Canadian Arctic Islands. The
glaciers of western Greenland, where 90% of Newfoundland's
icebergs originate, are amongst the fastest moving in the
world, up to 7 km per year.
and Arctic Icebergs Since 1912 when the Titanic
sank after striking an iceberg, ships or planes from the
International Ice Patrol, have searched the waters of the
North Atlantic off Newfoundland to report icebergs that have
broken off Greenland's ice sheet and drifted into the
shipping lanes between North America and Europe.
An Iceberg is a floating mass of freshwater ice that has
broken from the seaward end of a glacier or a polar ice
sheet. Icebergs are typically found in open seas, especially
around Greenland and Antarctica.
of the iceberg
and Icebergs Icebergs are the juggernauts of the
Arctic. Most of the bergs that prowl the shipping lanes of
the North Atlantic originate from glaciers on the West coast
Icebergs Icebergs are a common sight along the
coast of Newfoundland from March until July. They originate
from the glaciers of West Greenland where 30,000 - 40,000
are calved annually. Carried north around Baffin Bay they do
not appear in Newfoundland waters until their second year at
sea. Carried south in the Labrador Current they are most
abundant in and close to the arctic ice that reaches its
most southerly extent in late April.
of Ice During the peak of the last ice age,
one-third of the Earth's land surface was covered by thick
sheets of ice. Their high albedo reflected a great deal of
sunlight out into space, which cooled Earth and allowed the
ice sheets to grow. (See our Ice Ages web page.) Ice sheets
give birth to icebergs. This process is known as calving.
Most bergs are calved from ice sheets off the western coast
of Greenland and Antarctica. Icebergs are found in both the
Arctic and Antarctic regions. The bergs from these two areas
differ, however, in form and size.
Icebergs Bottle-green icebergs have often been
reported by visitors to Antarctica. The reason for their
green colour is still a matter of contention: Early reports
attributed the colour to high levels of metallic compounds.
Another has attributed the colour to an optical illusion
when blue ice is illuminated by a low lying red sun,
however, green icebergs stand out among white and blue
icebergs under a variety of light conditions. Yet another
states that the green colour is due to enriched yellow
substances derived from phytoplankton blooms.
Do Icebergs Form? Icebergs are blocks of
fresh-water ice that break off from glaciers and float out
to sea. Glaciers are formed in polar regions where snowfall
lasts for centuries, or even millennia, without entirely
melting, and is eventually compressed into ice.
of Atlantic Icebergs Most icebergs that reach the
North Atlantic Ocean come from the major glaciers of West
Greenland. Between 10,000 to 15,000 icebergs are calved each
year, primarily from the range between the Humboldt and
Ice Cap: Source for Atlantic Icebergs The
Greenland icecap contains 1/8th of the total global
ice-mass. The total ice-mass on earth is 30 million. cubic
km; Antarctica has 27 million.cubic km; Greenland 2.5
million. cubic km.
Never Sleeps It's hard to imagine anything more
elemental than an iceberg. Icebergs consist of frozen water.
End of story. Yet, the story of icebergs and their long
journey to the North Atlantic is oddly fascinating. Read on
to learn some of the basics about the bergs we'll be
searching out during our two-week expedition in
is Iceberg Alley? The area we call "Iceberg
Alley" is located about 250 miles east and southeast of
the island of Newfoundland, Canada. Iceberg Alley is usually
considered to be that portion of the Labrador Current, that
flows southward from Flemish Pass, along the eastern edge of
the Grand Banks of Newfoundland, to the Tail of the Banks.
Ice Patrol While icebergs are a constant
navigational hazard in the Arctic, the cold Labrador Current
carries some of them south to the vicinity of the Grand
Banks and into the great circle shipping lanes between
Europe and the major ports of the United States and Canada.
Photographs by Bruce Lane This is the second web
site gallery of iceberg photos by Bruce Lane.
| ICEBERGS | ICEBERG GIANTS