The B.C. Coroners Service said searchers will use heavy excavation equipment for another two days as they try to locate Rachel Webber near her family's home in the hamlet of Johnsons Landing.
The bodies of her father, Valentine Webber, 60, and 22-year-old sister Diana Webber were recovered last week after the July 12 slide.
Chief coroner Lisa Lapointe said Tuesday they believe there is a good chance they can find Rachel's body near where her father and sister were found.
"The family was very anxious that we return to the site ... Obviously it means a lot to the girl's mother that both of her daughters are recovered ... But we needed to reassess whether there was any meaningful possibility to recover Rachel Webber, and we feel on a balance of probability that we have a very good chance of success," Lapointe said.
"We feel two days of excavation on the outer edges of the area already searched will be successful. If they are not successful, we know we have exhausted every reasonable effort to locate her remains."
However, crews will not continue to search for the Webbers's neighbour, Petra Frehse, who was also buried in the slide and is presumed dead.
Lapoint said Frehse's cabin was higher up the mountain and hit harder by the slide.
"We found some very small artifacts of the home but really nothing that gave us any confidence that we could go back and be successful in another search in that area."
Slide a challenge for rescue crews
Meanwhile, Vancouver Mayor Gregor Robertson thanked members of the city's Heavy Urban Search and Rescue team for participating in the search.
Robertson said the knowledge gained by the team, which is also known as Canada Task Force 1, could be used if a disaster ever struck Vancouver.
The slide on the shores of Kootenay Lake occurred after a month of heavy rain allowed a mountainside to give way, sending trees and rubble roaring through the hamlet.
Search and rescue team member Capt. Rob Plecas said the debris was up to seven metres deep in some areas, but the scene wasn't what he expected.
"I found it absolutely amazing that there was no mud, nothing ever got dirty but the soles of my boots," he said.
"Everyone, and I myself too, was thinking we'd be walking in waste-deep, knee-deep mud. It wasn't like that."
Plecas said it was sad and frustrating to not find all four missing people, but praised the team's efforts.
"It would be like putting four needles at the bottom of a thousand haystacks and saying, 'Go ahead and find them,"' he said.
"The fact that we were able to use our training, our technology, our resources and, for lack of a better word, just gut effort and gut instinct to find the two is absolutely remarkable."