"This is Ann and Liv from the continent without wind," Liv's voice crackles over the satellite phone. The explorer's Dec. 28 daily update summed the expedition thus far: "We try to be optimistic — we are optimistic. But we most definitely need wind."

Now on their 52nd day on the ice, Ann Bancroft and Liv Arnesen, attempting to become the first women in history to make the 2,400-mile trek and sail across Antarctica, have cause to worry. The worldwide weather shift has caused a freakish lack of wind over the continent that often sees gusts howling upward of 100 m.p.h.

"On both our previous trips we had so much wind," Bancroft said in an earlier update. Hoping to spend New Year's at the Amundsen-Scott South Pole Station, the explorers are still over 300 miles away from this mental halfway point. And time, not to mention food, is running out.

Before departing, Bancroft and Arnesen agreed that Jan.15 would be about the latest they could depart the Pole. If they leave much later, winter will descend before they reach their destination, McMurdo Station on Ross Ice Shelf, some 1,300 miles away.

So far the women have averaged 18 miles a day, covering nearly 980 miles. To make the Jan. 15 deadline, they must pick up the pace and average over 30 miles a day, something they have exceeded only 16 times previous in the trip.

"It's making us a little punchy and a little weird," Bancroft said about the lack of wind. "It's also adding a bit of pressure to us."

Bancroft has been nursing a chronic shoulder injury and Arnesen, earlier in the expedition, broke her harness that connects her to the 250-pound sled.

Still, the explorers are in good spirits. They speak of wondrous skies, marvelous colors and a "kind of quiet in this vastness that is just mind boggling."

If the explorers are faced with not pushing past the Pole, they will have to fly out, a very costly endeavor.

In an interview at her home in Minneapolis last summer, Bancroft talked about the possibility of failure.

"We have the wisdom to know when it's time to stop. If it does happen, we'll feel good about that decision. This isn't 'get there at all costs.'"