Five hours later, Aug. 7 -- that somewhere between near-total darkness, temperatures approaching minus forty-three degrees Celsius at the landing strip and a weather window that could close within minutes, a medical retrieval from McMurdo Station was still possible.

a United States expeditioner had been evacuated from McMurdo Station, the American research base on the island's edge, and flown onward to Christchurch, New Zealand, for medical treatment. The rescue was one of only a handful of midwinter medical retrievals ever completed from the Antarctic continent during the months when the region is effectively sealed from the outside world.

The expeditioner's identity and medical condition have not been publicly disclosed. The Centre fo...