Page 22 - Sphere No.21 (Mar 2008)

out there we’re going to find it. Unfor-
tunately, we find that we only have good
visibility on the Grand Banks about 30
per cent of the time.”
Despite that narrow window of visibility,
the human eyeball is a useful back-up to the
electronic sensors. Observers looking out of
the C-130 windows can sometimes spot an
iceberg that went undetected by radar.
And while radar often accurately pin-
points an object in the ocean, it can’t always
distinguish between ice and a fishing vessel.
“Their profile is similar,” said the com-
mander. “A visual inspection can also determine the size and
shape of an iceberg. For example, a large iceberg that is the size
of a small gym is going to last a whole lot longer than a small ice-
berg that might be the size of a small house. So we need to know
that. If the radar doesn’t tell us that, the humans in the windows
can supplement that.”
On average, the ice patrol expects an average of 250 icebergs
per season, but the actual count varies widely. In 2005 and
2006, a combined total of just 11 icebergs were tracked south
of the 48th parallel; in 2002 and 2003, the ice patrol averaged
900 icebergs per season. Last year, 324 icebergs were spotted.
“It’s not uncommon to have lighter years offset by far more
dangerous years,” said Commander Rogerson. “It only takes
one iceberg and one ship at the same place at the same time
and that’s going to be a problem.”
The Grand Banks – often described as the stormiest, foggiest,
20 SPHERE
most dangerous part of the North Atlan-
tic – is home to Iceberg Alley, the route
most icebergs typically follow as they drift
southward towards the Caribbean and
melt into the ocean.
Their two-year journey begins at the
West Greenland glaciers, where up to
15,000 icebergs break away from the main
ice sheet annually and slowly drift south.
The LabradorCurrent carriesmost of these
icebergs through the Grand Banks.
There, the icebergs cross international
shipping lanes and drift near a trio of
offshore oil fields that pump crude from the seabed. Icebergs
pose a threat to ships as well as to the oil rigs and production
platforms at the Hibernia, Terra Nova and White Rose oil fields
operated respectively by ExxonMobil, Petro-Canada and Hus-
ky Energy, a Hutchison company.
Dealing with ice is part of daily operations in these oil fields
during iceberg season. The Hibernia platform, which sits on
top of a concrete pedestal, was designed to withstand a collision
with a one-million tonne iceberg. At Terra Nova and White
Rose, the production ships are equipped to disconnect quickly
from the seabed if an iceberg drifts too close.
While the ice patrol leaves ice management to the oil com-
panies, it does collect ice data from them. St John’s-based Pro-
vincial Aerospace Ltd monitors icebergs and sea ice in the
Newfoundland oil patch and feeds this information to the IIP.
The ice patrol also works with other agencies, including the
A wreath is dropped into the
ocean at the annual memorial
service for the Titanic.
To help collect data,
the ice patrol deploys
oceanographic buoys to
track ocean currents and
uses satellites to measure
water temperature.