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Things You Need to Know About Icebergs

Things You Need to Know About Icebergs

It is common knowledge that icebergs are large floating chunks of ice. However, these frozen behemoths are very deceptive, and there is a lot that we don't know about them. In this article, we shall look at a few interesting facts, such as where icebergs come from, how they are formed, and much more.
ScienceStruck Staff
Fast Fact!

The term 'iceberg' refers to large pieces of ice that are wider than 5 meters (16 feet). Smaller chunks of ice are known as 'growlers' or 'bergy bits'.
The term 'iceberg' refers to large pieces of ice that are wider than 5 meters (16 feet). Smaller chunks of ice are known as 'growlers' or 'bergy bits'. Like penguins or polar bears, icebergs too are very unique and symbolic to the polar regions, so much so that Greenlanders once used them to identify seasons and towns. The term 'iceberg' is borrowed from the dutch word 'ijsberg', which literally means ice mountain. This name is apt, as icebergs are usually large, magnificent mountainous masses of free-floating ice, that wander the oceans till they melt. While these slabs of ice look sterile and devoid of life, they actually harbor complete ecosystems, and have a big impact on any ecosystem that they may pass through.
Icebergs seem to either exude awe or an aura of danger, as they move around in oceans at higher latitudes, creating an atmosphere of peril for ships, similar in manner to naval mines. However, they also hold a lot of promise. Apart from helping oceanographers and other scientists in their studies, it has been proposed to tow icebergs to drought stricken areas to solve water shortage problems, but the logistics and possible environmental damage has deterred any such effort to be made so far.
Interesting Facts About Icebergs
Origins and Formation
When glaciers on land form due to snowfall over several hundred years, each new layer of snow compresses the ones below it, until glacial ice is formed around 70 meters below the surface. The glacier gradually creeps towards open sea under its own weight, and once it reaches the water, the edges of the glacier breaks off due to the motion of the tides, and slips into the ocean, and icebergs are formed. This process is called calving. The ice usually floats with the sea currents, gradually melting with a fizzing sound as it moves towards warmer waters.
Most of the world's icebergs come from around Antarctica, the glaciers of western Greenland, and the glaciers near Canada's arctic area. As of now, 30,000 - 40,000 icebergs are formed each year. Because they have an interior temperature of -15 to -20 degrees Centigrade, many of them travel thousands of miles and take at least a year or two to melt completely.
Composition
Due to the fact that icebergs are found at sea, they are wrongly assumed to be formed of salty sea water. In reality, they are made of pure freshwater and snow. Therefore, the ice is completely safe to consume. In rare cases, melted water in the glacier or dust from volcanoes may enter the iceberg's crevasses. This can cause the structure to acquire blue, brown, or blackish streaks.
Physical Characteristics
streaked-iceberg
Flipped Iceberg Showing Blue Streaks
Icebergs are made of ice that may be around 10,000 years old. Due to their massive size, many of them weigh over 10 million tons, although you may also find a few smaller ones which could weigh anywhere between 100,000 and 200,000 tons. Despite their weight, they float in ocean water, because water is denser as a liquid (density of seawater is 1025 kg/m3) than as a solid (density of pure ice is 920 kg/m3). Also, icebergs contain a large amount of air bubbles, which gives them their white appearance, and increases their buoyancy.
However, due to their immense weight, they float with only about ⅞ to ⅒ of their mass above the water. Also, the width of the ice below the water is around 20 - 30% larger than what is above the surface. So, the only natural source affecting their movement significantly is the ocean currents, which push them around at a leisurely pace ranging between 0.4 and 2.2 mph. When near land, icebergs often get stranded, and create deep and wide troughs in the sea bed, which can last for decades.
Iceberg Types
Icebergs can be classified into various categories, depending on their size and shape:
Classification by Size
  • Very Large Iceberg: These are the biggest and heaviest varieties, and icebergs come under this category if they are larger than 75 meters in height, and 200 meters in length.
  • Large Iceberg: The second-largest type, these can be as big as a sports stadium, with heights ranging between 46 - 75 meters in height, and 121 - 200 meters in length.
  • Medium Iceberg: Getting as big as a medium-sized hotel, these range between 16 - 45 meters in height, and 61 - 120 meters in length.
  • Small Iceberg: These small icebergs are about as big as a small building, and range between 5 - 15 meters in height, and 15 - 60 meters in length.
  • Bergy Bits: Although not considered as true icebergs, these cottage-sized chunks of ice come in sizes between 1 - 5 meters in height, and 5 - 15 meters in length.
  • Growlers: The smallest type in the iceberg family, these pieces of ice are smaller than 1 meter in height, and 5 meters in length.
Classification by Shape
iceberg-shape-chart
  • Tabular: They have a generally flat appearance, and their height is significantly lesser than their width/length. Most of them are seen to be composed of numerous horizontal bands of ice of different shades.
  • Blocky: These are also a flat-topped variety, but they have steep, tall sides and heights, which are not very different from their width.
  • Wedged: Another flat-surfaced type, these icebergs have steep, tall cliffs on one side, from where the top slopes gradually go downward to the opposite side, giving it the appearance of a wedge.
  • Dome: Largely similar to tabular and blocky icebergs, domes differ only by having a smooth and rounded top.
  • Pinnacle: This variety gets is name by having at least one prominent spire or pyramidal section of ice on it.
  • Dry Dock: These icebergs have two or more pinnacles, and also a U-shaped slot between the spires close to the water level.
Depending on the shape and size, icebergs can be very unstable, and can even flip over without any warning, which can be highly dangerous. The action of rolling over can release as much energy as an atomic bomb, resulting in tsunamis and earthquakes. While the tabular varieties are generally stable, the wedge or dome-shaped ones are prone to rolling around.
The World's Largest Iceberg
The tallest known iceberg was seen in the North Atlantic ocean, which rose approximately 170 meters above sea level. Considering that the majority of its mass was below water, it was estimated to be as tall as a 60-storey building. However, this is not even close to the size of the biggest icebergs on record. Recently, in 2000, an iceberg named B-15 was spotted by satellite imagery. It was almost as big as the state of Connecticut, measuring over 4,200 square miles. However, even this iceberg was dwarfed by a tabular iceberg spotted by the USS Glacier in 1956, which measured more than 12,000 square miles, and was estimated to be larger than Belgium.
Dangers That Icebergs Pose to Ships
titanic-iceberg
Titanic and the Iceberg
The ice in icebergs is about 10% as strong as dry concrete, and although this does not seem very hard, the size, weight, and momentum of these huge chunks of ice make them extremely dangerous to colliding ships. The large underwater mass of ice is usually sharp and not easily visible, especially in the case of bergy bits and growlers, increasing the chances of an accident. Therefore, the idiom 'tip of an iceberg' is used to indicate situations where a person may be able to see only a part of the whole picture, leading to problems.
An area located 250 miles east and southeast of Newfoundland has been named Iceberg Alley, due to the exceedingly high number of icebergs there, which make conditions for shipping quite treacherous. In a collision with an iceberg, an immense force of hundreds of tons is subjected on the ship's hull, which causes massive catastrophes such as the RMS Titanic disaster of 1912. In that accident, the British ocean liner was traveling towards New York through the Iceberg Alley when it struck an iceberg and sunk with over 1,500 people. While most sea disasters take place due to rough seas and storms, the Titanic sank due to the sea being too calm, as the lookouts could not see waves crashing onto the iceberg, nor the phosphorescence of algae, on that moonless night.
To stop such disasters from ever happening again, the US and 12 other nations got together and created an organization named the International Ice Patrol. Today, this organization uses radar and airplanes to monitor the movement of icebergs which are floating into major shipping lanes. Satellite data is also used to monitor large icebergs floating around Antarctica. However, since the number of ships have increased drastically since 1912, the chances of an accidents still exists. In fact, between 1980 and 2005, there have been over fifty incidents involving sea vessels and icebergs.
Tips to See Icebergs
  • Your best bet for viewing icebergs is to travel towards the north on the eastern coast of Newfoundland and Labrador, as most icebergs are located in this area near Greenland. It is recommended that you take a guided tour, as the local tour operators would have the requisite experience to get you close to the icebergs without putting you in danger.
  • Although much riskier, people also use individual kayaks or scuba dive near the icebergs to get some great photographs. But one should never attempt to climb onto one, as the risk of injury and death is quite high.
  • To get some good photographs, search for different colored streaks, tunnels, caves, rocks, etc., embedded inside the ice. Also look for seabirds that might perch on top of the iceberg. If the bird flies off suddenly, there is a chance that the ice is breaking apart or rolling over, which is also a real visual treat.
  • The best time to view icebergs is late May or early June, when there is a good chance of spotting seabirds and whales as well.
  • If you are planning to watch icebergs from land, make sure that you carry a binocular or telescope to increase the chances and quality of a sighting.
Why are Icebergs Important?
Icebergs play an important role in the sea, by leaking nutrients into the ocean waters around them. Studies have shown that areas near icebergs are usually teeming with sea-life, such as fish and plankton. The freshwater being added into the sea can influence ocean currents around the world, which can drastically affect global climate. Therefore, it is important that oceanographers pay significant attention to them. By studying the breakup of icebergs as they near warmer waters, scientists can predict how the ice shelves of the Arctic and Antarctic region will react to the warming climates of the world in the future.