The A factor hits summer logistics

Logistics planners in Antarctica know they must never lose sight of the A (for Antarctic) factor. Right around Antarctica this past summer, heavy ice conditions in key localities affected the shipping activities of a number of countries. Australian shipping was affected by the besetment of Polar Bird for five weeks in Prydz Bay (see following story), but the US and Great Britain also had their trials.

Up to last summer, the record sea ice extent to the north of McMurdo Station was 74 km; in November 2001 it persisted to almost 120 km from the base, forcing the use of a second icebreaker to help cut the required channel through to the base to allow resupply ships to enter, at an estimated cost of A$6 million dollars. Difficult weather conditions also hampered activities at Amundsen-Scott, South Pole, where mainly poor visibility prevented 50 scheduled flights from arriving. Temperatures below minus 20°C following early spring temperatures below minus 80°C also hampered work on construction of a replacement Amundsen-Scott station.

Heavy ice restricted UK activities in the Weddell Sea, east of the Antarctic Peninsula. In December, the resupply ship RRS Ernest Shackleton was unable to reach Halley station, delaying resupply by two months. The following month the ship eventually made landfall at Drescher Inlet, 200 nm north-east of the station, from where personnel and essential and priority cargo had to be flown in.

Southern Ocean crossings were a mixed bag. Barbara Wienecke of the AAD, travelling between New Zealand and the Ross Sea between early December and mid-January, reported ‘mill pond conditions’, while on 31 January south of Australia Aurora Australis encountered the effects of an intense low. The ship’s captain, Les Morrow, reported a 24-hour storm with 50-knot winds and short 10 m swells that created an uneasy, pitching ship motion and caused water to be shipped over the bow and even over the mezzanine level above the stern trawl deck. Winds at one stage reached 60 knots with wave heights peaking at 16 m, and the ship was forced to heave to for a long period.

On land, the ‘A factor’ also affected members of the Prince Charles Mountain geology expedition. Field leader, Andy Cianchi, reported a blizzard cycle of four days around Beaver Lake and Lake Terasavoja – clouding over for a day, then blowing a two-day blizzard, then clearing and starting again, allowing only one working day in four and one flying day every two weeks. In contrast, Macquarie Island experienced very dry conditions, particularly in January, helping a terrestrial ecologist, ornithologists and geologists to complete extensive fieldwork. Station leader Robb Clifton boasted about not wearing his waterproof jacket for 10 days straight – something of a record in predominantly cool, wet windy Macquarie Island, affectionately called the green sponge.

Dana Bergstrom, Eric Woehler, Rob Easther and Annie Rushton, AAD