Northland Discovery

Boat Tours

P.O. Box 728

St. Anthony, NL

Canada AOK 4SO

 

Tel: (709)454-3092

1877-632-3747

Fax: (709)454-3095

 

WHERE DO ICEBERGS COME FROM?

Most of the icebergs that reach the North Atlantic come from 100 major glaciers in Greenland. The others come from glaciers in northern Ellesmere Island. Approximately 40,000 icebergs will calf from these glaciers to join the cold arctic seas. Of these 40,000 icebergs, 10,000- 15,000 icebergs calf from 20 major glaciers between Jacobshaven and Humboldt of West Greenland. It is estimated that these glaciers account for 85% of the icebergs that reach the Newfoundland and Labrador coast. The East Greenland glaciers produce about half the number of West Greenland glaciers, and account for 10% of the icebergs that reach the province. The remaining 5% of the icebergs are thought to come from northern Ellesmere Island. Out of the 40,000 icebergs that calf each year, on average 2000 pass Cape Chidley, 1400 icebergs will pass Belle Isle and nearly half of these (400-800) will reach as far south as St. Johnís.

 

HOW DOES AN ICEBERG FORM?

Snow falls on the glacial ice cap of Greenland. After several months the snow forms a granular snow called a firn. Over thousands of years large amounts of snow continue to accumulate and compact to form a very dense ice. Eventually the ice cap will reach such an enormous weight that it will begin to flow down mountainsides and valleys to the coast. This journey is often aided by spring water run-off allowing the rivers of ice known as glaciers to move as much as 65 feet a day. At the waters edge, tidal fluctuations result in the weakening of the ice due to constant wave action underneath the glacier. The warm spring temperatures also add to the weakening of the ice. Eventually this will cause the glacier to break, allowing smaller pieces of ice or icebergs to enter the sea. This is called calving. Some of the ice of these bergs can be as much as 15,000 years old.
 

HOW DO ICEBERGS GET HERE FROM WEST GREENLAND?

When icebergs calf and enter Baffin Bay from the West Greenland glaciers, the northerly flow of the West Greenland Current pushes them in a north-northwest direction until they reach northern Baffin Bay. Here they eventually strike the southerly flow of the Baffin Bay Current, which forces the icebergs to coastal Labrador. The southerly flow of the Labrador Current will then push the bergs further to Newfoundland. This current allows some icebergs to reach as far south as the Grand Banks, off the south coast of Newfoundland. This journey can take as long as 2-3 years (Many icebergs become entrapped in the frozen arctic seas of Baffin Bay during their first winter of travel or become stuck on the ocean floor for several months). Some rare sightings have even been recorded off the coast of Bermuda.


WHAT IS AN ICEBERG COMPOSED OF?


Iceberg ice is pure fresh water. As mentioned earlier, the ice is just highly compacted snow particles; a condensed water vapour that fell from the earth's atmosphere thousands of years ago. The only minute impurities that may be in the ice would come from dust particles created from volcanic activity many centuries ago. It is unlikely to find any pollutants in it. Depending on how dense the ice is, there might be air bubbles trapped inside. The air bubbles give the iceberg its characteristic white appearance because of its reflective property of white light. Sections of icebergs with no air bubbles have a blue appearance. Some icebergs will even have streaks of blue on them. This is caused by bubble free melt water refreezing in the cracks or crevices of the glacier as it crept to the coast. In the summer the core temperature of an iceberg can still remain -15 to -20įc while the surface can hover at 0įc.


HOW MUCH OF AN ICEBERG IS BELOW WATER?


Typically only one-seventh to one- eight of an iceberg is above water, the rest is hidden below the surface. From this we can appreciate how powerful the phrase "tip of an iceberg" really is. This does not mean that the ice underneath the water is six or seven times deeper. It is six or seven times larger in mass. In fact, the ice underneath is only 20-30% deeper then the height of the ice above.


HOW BIG CAN ICEBERGS GET?

Icebergs are very variable in size. Some come in smaller chunks of ice known as "growlers" or "bergy bits." These are usually pieces that break off from larger icebergs. Growlers can range from a small car to a large house in size. Bergy bits are even smaller. These icebergs can still be very dangerous to shipping because they are often low on the water, hidden by choppy seas and they are sometimes invisible to radar. Along coastal Labrador and Newfoundland, icebergs are often observed a staggering height of 150-200 feet tall, 75-100 feet long, and 50-75 feet wide. Itís a spectacular site. The tallest arctic iceberg was spotted in 1967 which towered some 550 feet above the ocean surface. This is about half the size of the Empire State Building. For sheer mass, the largest arctic iceberg was recorded near Baffin Island in 1882. It measured some 7 miles long and 3.6 miles wide. The largest iceberg ever recorded worldwide came from the Antarctic. In 1956 the iceberg was observed measuring an astounding 207 miles long and 62 miles wide.        

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© Northland Discovery Tours, Newfoundland, Canada. Updated Jan.2013