The alarm was raised by mountain radio from the Woolshed Creek hut shortly after 4pm and police, search and rescue and the alpine search and rescue teams were deployed.
A helicopter conducted an aerial search while there was still daylight and located some items, including what was believed to have been a pack, in deep pools in the gorge area. Searchers were expecting the worst.
When the Guardian spoke to the police last night they were yet to speak to the woman and she was yet to be checked out by medical personnel, although early indications were she did not have serious injuries.
"She had definitely been swept into a narrow gorge which is known as the Impassable Gorge area," Mr Jackson said. Searchers were not hopeful and were expecting a long night looking for her when she, incredibly, walked out alive.
"The best we can tell at this stage is that she has ended up 2-3km along the Woolshed Creek."
Police released little information about the search while it was happening, as they were aware there was a large school group in the area at the time as well, and they didn't want to cause panic among worried parents.
- Ashburton Guardian