Icy Giant Settles in at Casey

Iceberg in the distance
Iceberg B15G (Photo: Christopher R Clarke)

Thursday 19 May, 2005

An iceberg more than twice the size of Malta has arrived in the backyard of Australia's Casey station in Antarctica,

The 50 km-long iceberg, 788 square kms in area, is known as B15G. It is part of a massive iceberg, B15, that broke away the Ross Ice Shelf in Antarctica in March 2000.

Station leader Jeremy Smith says that B15G is clearly visible as a long ice cliff stretching along the horizon.

"As the Antarctic winter closes in B15G appears as a grey line occupying ninety degrees of arc and defining half our horizon, in places gleaming where the sun reflects off an ice cliff. But often it is sulking in shadow and difficult to distinguish from the sky in the background," Dr Smith said.

Dr Smith says that a mathematically-minded wag on station has calculated that the iceberg comprises more than 220 cubic km of ice, enough for 15,000,000,000,000,000 (or 15 thousand million, million) ice cubes. It also equates to around 200,000 billion litres of fresh water.

A number of these huge icebergs have spent the past few years off the coast of George V Land (approximately longitude 150 E) to the east of the Mertz Glacier.

B15G has been drifting slowly from east to west with the ocean current known as the East Wind Drift and passed the French Antarctic station, Dumont D'Urville in August 2004.

In the past months it has moved a distance of more than a thousand kilometres, past Law Dome and arrived in Vincennes Bay off Casey station the week before last.

Glaciologists say B15G now appears to have become grounded and could stay for days, weeks or even months. In time, though, it is expected to continue its westward drift around the continent.

Meanwhile there are no known immediate negative impacts for wildlife in the area and there is no concern of damage to landforms.

B15G is the first iceberg of such huge proportions observed to have entered Vincennes Bay having moved about 150 kms south over the continental shelf, well south of the typical drift path expected to be followed.