The head of a wind turbine lies on the ground at Australia's Antarctic Division's Mawson station after it broke off narrowly missing a storage building

The blades of a wind turbine at an Australian Antarctic base broke off and narrowly missed a storage building as they crashed to the ground, officials said Wednesday, forcing the icy outpost to switch to backup power.

The head of the turbine, one of two at Mawson station, plunged 30 metres (100 feet) on Tuesday evening, despite there being only moderate gusts of at the time.

All 13 members of the expedition at the station are safe, and were inside their living quarters at the time, said Rob Wooding, general manager of support and operations at the base.

The second turbine was deactivated as a precaution, with the base switching to its diesel generators.

"While Mawson can experience regular blizzards, the conditions over the last few days have been moderate, with wind gusts of up to 40 knots," he said.

The was built by the German company Enercon, and went into operation in 2003.

"The cause of the incident is unknown and will be fully investigated," said Wooding, adding that regular maintenance was carried out on the turbines.

Mawson, named after polar explorer Sir Douglas Mawson, is one of three Australian bases in Antarctica. Established in 1954, it is the longest continuously operating south of the Antarctic Circle.