Update, 9:50 a.m. EDT, Tuesday, Sept. 14: The Orion plane was able to land at McMurdo's landing strip, refuel and evacuate the man, who was said to have a serious medical condition, the Associated Press reported. The man was flown back to New Zealand and taken to Christchurch Hospital.

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A rescue plane is in the air en route to McMurdo Station in Antarctica in an effort to evacuate an American crew member from the U.S. research station, LiveScience has learned. The man is said to be in serious but stable condition. Officials have not said if he is ill or injured.

The call for a medevac team went out on Thursday (Sept. 9), but poor weather conditions in Antarctica have thwarted attempts to land planes to take the sick man back to Christchurch, New Zealand.

"Weather continues to be an issue," said Will Colston, director of Antarctica logistics for the U.S. National Science Foundation. "Weather can change at any point in time."

After an aborted attempt to send in a New Zealand Air Force Orion aircraft early Sunday, the same craft is attempting another landing at McMurdo's air strip and is about three hours out from the station. The trip from Christchurch takes about 6 hours in the Orion plane. [See images of Antarctic researchers.]

The earlier attempt was thwarted by sudden blizzard conditions, which can crop up unexpectedly in Antarctica, particularly during this time of year as winter transitions to spring and the sun is heating the atmosphere during the day, creating potential disturbances.

Though "blizzards are very common any time of year in the Antarctic," said Rebecca Batchelor, a researcher with the National Center for Atmospheric Research in Boulder, Colo., who spent most of 2003 and October 2005 to October 2006 at McMurdo. "The weather is very changeable."

Sick scientists and support crew members have some medical support at McMurdo, which George Blaisedell, operations manager for the NSF's Antarctica logistics said was the "most advanced facility" in Antarctica. Blaisedell likened the medical facilities at McMurdo to those in a small, rural American town. Internet and phone connections allow McMurdo residents some capability of consulting with medical experts elsewhere.

The exact condition of the sick man was not divulged due to privacy issues, Colston said, though he confirmed that the man was a support crew member that works for the company Raytheon, which has a support contract with McMurdo.

The most common, non-emergency ailments at McMurdo are typically bruises and sprains, due to the physical nature of much of the work and the harsh terrain, frost nip, dehydration (due to the desert conditions of Antarctica) and sunburn, from low-angle sunlight reflecting off the snow.

Conditions are currently clear in Antarctica and Colston and Blaisedell said all signs point to the plane being able to make a successful landing. They are receiving updates on the medical situation there about every four hours and expect to hear whether or not the landing will happen in the next hour or two, after the plane passes the point of safe return — after this point in its flight, the plane doesn't have enough fuel to return to Christchurch. Aborted flights are not uncommon and are called "boomerang flights," Batchelor said.

If the current attempt is unsuccessful, officials will continue to make rescue attempts as long as the medical situation warrants, they said. Alternatives to the Orion plane may have to be made as the plane and its crew are not available indefinitely due to other obligations of the New Zealand Air Force. Colston and Blaisedell noted that they were grateful for the support and assistance from the New Zealand government.

During winter in the Southern Hemisphere which is now, only about 100 people are at McMurdo, most of which are support staff, Batchelor said. During the summer research season, that number balloons to around 1,200 people.

The current conditions at McMurdo are temperatures of minus 31 degrees Fahrenheit (minus 35 degrees C), with a wind chill of minus 58 F (minus 50 C).

During blizzard conditions, the temperature actually warms up, Batchelor said in a telephone interview, though winds can reach up to hurricane strength and the blowing snow means that "the visibility goes down to next to nothing."

Weather forecasting in Antarctica is minimal compared to the United States, as researchers are only located at six sites around the continent, with 40 automated sites supplementing their measurements scattered around a continent that is the size of the United States and Mexico combined, plus a little extra.

The dearth of measurements make accurate and long-ranging forecasts difficult, though NCAR scientists have established an Antarctica-specific forecasting system.

Andrea Thompson is the Managing Editor for OurAmazingPlanet, a sister site to Livescience.