As she skis across Antarctica, Felicity Aston is taking on dangers including crevasses, storms, injuries and frostbite. Her biggest challenge, though, has been adapting to solitude in the seemingly endless expanses of white.

For more than three weeks, she has been skiing toward the South Pole pulling two sledges packed with supplies. Aston is attempting to become the first woman to cross Antarctica alone, and has covered about one-third of the journey of more than 1,700 kilometers.

The British adventurer expects to reach the South Pole this week, then pick up more supplies and head out again for the other side of the frozen continent. She says the emotional toll has been much greater than she expected.

"When that plane disappeared and left me on the wrong side of Antarctica all by myself with two little sledges, it really hit me that I'm completely responsible for myself," she told The Associated Press in an interview by satellite phone. "It's just you. You have to sort out your problems, and that makes you feel very vulnerable."

When alone in Antarctica, little problems can easily become big problems.

One ski binding is slightly out of alignment and has been making her ankle ache.

The three cigarette lighters she brought to start her camp stove suddenly stopped producing a flame in the cold, leaving her with only matches for a time, though she finally managed to get the lighters working again, intermittently.

She's been fighting a cough. And her breath freezes and forms icicles on her mask as she skis in temperatures of -30 C and below.

After each day on the ice, she pitches her tent, cooks a freeze-dried meal on her stove and posts messages on Twitter. "Ice coating my fur hood and icicles hanging off my mask and goggles made me look like a real polar explorer today," she posted on Saturday.

Sometimes, she raves about the beauty of the landscape. Other times, she says she feels tired, bitterly cold or even a bit overwhelmed.

"Yesterday was the first day I didn't burst into tears at any point. Must mean I'm getting used to this finally?" she said in a post on Twitter last week.

The 34-year-old used to work as a meteorologist in Antarctica and is a veteran adventurer who has led team expeditions in the Antarctic, the Arctic and Greenland. She said she decided to attempt her first solo crossing to test her personal limits and also because she was curious about being on her own.

Aston set out on Nov 25 from the Ross Ice Shelf, climbing a glacier dotted with crevasses in the Transantarctic Mountains before emerging onto the continent's vast central plateau.

She initially hoped to reach the South Pole by Dec 13, in time for the centennial celebration of Norwegian Roald Amundsen's achievement in leading the first team to reach the pole. But initial flight delays and a storm slowed her progress.

Some days, Aston has skied through drifting snow. Others, she has soldiered through sastrugi, the waves of ice sculpted by fierce winds.

This time of year, the sun never sets in Antarctica. It makes a big circle in the sky.

"You've got a halo around the sun, but then directly beneath the sun on the snow on the horizon is like a big flare of light," Aston said in one of the audio updates she regularly posts online.

In addition to two satellite phones, she is carrying solar panels to charge her batteries and a GPS to track her position. While skiing, she listens to an MP3 player with songs by Aretha Franklin and others.

She said posting on Twitter helps her feel a little less alone. In one message, she wrote: "I felt tired today but I could hear my Mum's voice encouraging me, 'Just keep moving. Keep moving forward.'"

Associated Press