HALIFAX — As two gargantuan islands of ice continue to slowly drift southward from the Arctic, an iceberg expert says there’s a slim chance they could reach the Grand Banks as early as August, posing a remote threat to the Hibernia oil platform.
Luc Desjardins, a senior forecaster with the Canadian Ice Service, stressed that these unusually large icebergs — the smaller one is about the size of Manhattan — could break up or get stranded in some distant bay in the months ahead.
But the lumbering, flat-topped pair have made steady progress since last September when they broke away from an even larger tabular iceberg, known as Petermann Ice Island 2010.
“If the bigger ones reach the Grand Banks, they are shallow-drafted and they can make their way onto the Grand Banks and they can hit Hibernia,” Desjardins said in an interview.
“But that would be a flukey, one-in-a-million chance.”
One island measures 84 square kilometres, the other 65.
Satellite images confirmed the parent berg, which calved from the Petermann Glacier in northwestern Greenland on Aug. 5, was a staggering 280 square kilometres, making it the largest ice island to break away in the Arctic in a half-century of observation.
Trudy Wohlleben, one of Desjardins’ colleagues in Ottawa, was the first to confirm the birth of the ice giant as she scanned NASA satellite images in early August.
The spectacular find made headlines around the world.
Since then, its two largest offspring — dubbed PBII-A and PBII-B — have travelled more than 1,000 kilometres from Nares Strait on the east side of Ellesmere Island to the east coast of Baffin Island, not far from the community of Clyde River.
They are currently moving south at an average speed of seven kilometres per hour, but will pick up speed once they emerge from the pack ice this summer.
“The threat for those people who are trying to handle icebergs around the drill ships and platforms on the East Coast is the fact that these suckers are humongous,” Desjardins said.
“They can’t go around with ships and lasso them and tow them away. ... The berg would probably tow the ship away. ... It’s that kind of information that scares them.”
A spokesman for the Hibernia consortium, Merle MacIsaac, said the project’s partners have long had an ice management plan in place to maintain safe operations and protect the environment.
“At this stage, we don’t think it’s appropriate to speculate on the future direction ... of the icebergs,” he said in an interview from Halifax.
The rig has never been hit by an iceberg, though scores of small icebergs have been towed away or blasted with water cannon.
The Hibernia website says the rig is built to endure an indirect hit from the largest of icebergs.
“It can withstand contact with a six-million-tonne iceberg, estimated to be the largest that can drift into that water depth and only expected once in 10,000 years, with repairable damage,” the site says.
Despite their immense bulk, the two frozen slabs extend only 60 metres below the water, which means they are unlikely to run aground on the relatively shallow Grand Banks. The Hibernia platform sits on the ocean floor in 80 metres of water. It cannot be moved.
As for the other drill rigs and floating production platforms off the East Coast, all can be moved in the event of an emergency.
“The other two (floating platforms) would just pull up stakes and move for a while,” said Sean Kelly, spokesman for the Canada-Newfoundland and Labrador Offshore Petroleum Board. “Hibernia would have to do something different.”
Meanwhile, about a dozen smaller ice islands, measuring from one to 10 square kilometres, have already floated 450 kilometres ahead of their largest cousins, drifting near Nunavut’s Broughton Island in mid-January.
However, all of the ice islands — big and small — will endure their roughest treatment when the pack ice recedes and they are exposed to the open ocean, where storm-tossed waves are sure to fracture the islands into smaller chunks.
“Mother Nature is going to take her toll on each and every one of them,” Desjardins said. “(But) even a two-square-kilometre piece is still unmanageable. So it becomes a threat.”
In the late 1800s, an ice island measuring at least eight kilometres long made it as far as St. John’s harbour.
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On the web:
A satellite beacon was dropped on the smaller of the two islands, PBII-A, on Sept. 17. Its progress can be tracked at http://sailwx.info/shiptrack/shipposition.phtml?call47557