What are the Sizes and Shapes of Icebergs?

At the glacier's terminus or end, huge slabs of ice are weakened and then broken by the action of the rising and falling tides. This process is called calving and results in an iceberg's birth. By the time these mountains of ice enter Baffin Bay they have seen nearly 3,000 years pass.

In order for an iceberg to reach the North Atlantic the currents typically take it from Baffin Bay through the Davis Strait and Labrador Sea. This is a long trip and most icebergs never make it. Most icebergs melt well before entering the Atlantic Ocean. One estimate is that of the 15,000 to 30,000 icebergs produced annually by the glaciers of Greenland only one percent (150 to 300) ever make it to the Atlantic Ocean. When an iceberg does happen to reach the Atlantic its long and traveled life quickly

Iceberg size classification
Size category	Height (ft.)	Height (m)	Length (ft.)	Length (m)
Growler	less than 3	less than 1	Less than 16	less than 5
Bergy Bit	3–13	1–4	15–46	5–14
Small	14–50	5–15	47–200	15–60
Medium	51–150	16–45	201–400	61–122
Large	151–240	46–75	401–670	123–213
Very Large	Over 240	Over 75	Over 670	Over 213

Iceberg shape classification
Shape category	Description
Tabular	Steep sides with flat top. Very solid. Length-height ratio less than 5:1
Non-Tabular	This category covers all icebergs that are not tabular-shaped as described above. This includes bergs that are dome-shaped, sloping, blocky, and pinnacle.

Iceberg Shapes

Tabular: A flat-topped iceberg. Most show horizontal banding.
Blocky: A flat-topped iceberg with steep vertical sides.
Drydocked: An iceberg which is eroded and a U-shaped slot is formed. Pinnacled: An iceberg with a central spire, with one or more spires.
Wedged: An iceberg which is flat on top and with steep vertical sides on one end and sloping on the other.

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Alpine Mountains Revealed Beneath Antarctic Ice

A series of prefabricated buildings perched on stilts create a boxy but unremarkable hamlet on the Antarctic ice. What is astonishing about this research base is that it is set 500 metres above the peaks of a 3500-metre mountain range.

The Gamburtsev mountains are not a new discovery – they were first located 50 years ago by a team of Russian scientists. But little was known about their scale and morphology. Now, an international team has returned with data revealing that if you could strip away the ice, the view would look rather like the European Alps.

The existence of this mountain range, called the Gamburtsev Mountains, shocked the Russian scientists who first discovered it more than 50 years ago, and mystery still shrouds the nearly 750-mile-long (1,200-kilometer-long) series of subglacial peaks.

At the International Polar Year conference in Oslo, Norway, scientists unveiled new radar images of an area of the mountains the size of the state of New York.

"What we'd shown before was an estimate based on gravity data — a little bit of a coarse resolution tool," said Robin Bell, a senior research scientist at Columbia's Lamont-Doherty Earth Observatory in New York. "What we showed at this meeting was the radar data. It's like going from using a big, fat Sharpie [pen] to using a fine-tipped pencil."

What the pictures reveal, Bell said, is spectacular: a dramatic landscape of rocky summits, deep river valleys, and liquid, not frozen, lakes, all hidden beneath the ice.

Bell was among a team of scientists from seven countries who spent two frigid months collecting geophysical data in the remote antipodean wilderness via sophisticated, aircraft-mounted instruments in late 2008 and early 2009.

Mountains in the Antarctic interior are few and far between. Many are a special kind of mountain called a "nunatak". The Trans Antarctic Mountains that stretch from one side of the continent to the other break through the ice cap in places to form such nunataks - they are mountains that are surrounded completely by an ice field. A sort of cold version of the ocean and islands except that these are on land and raised high above sea level.

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