The search for missing bushwalker Lily Hooper has entered its sixth day, with police continuing to use a thermal-imaging helicopter overnight and examining telecommunications data in an effort to trace her last movements.
The 18-year-old left her home south-west of Sydney on Wednesday morning to go hiking in the Nattai National Park in the Southern Highlands.
Her car was later found near the Bonnum Pic Walking Trail, but despite an extensive multi-agency operation beginning on Wednesday night, there has been no trace of the experienced bushwalker.
Hume Police District Chief Inspector Brendan Bernie told reporters at the site that inclement weather had not affected search efforts in the "vast, dense bushland".
He said family members, who have been with emergency services at the site since Wednesday, were distressed but holding out hope.
"Lily's family is holding up amazingly well," Chief Inspector Bernie said.
"They are obviously very distressed about the situation.
"But they are supporting us and helping us with information about equipment she may have had before she went on her trip.
Chief Inspector Bernie said crews had continued searching throughout the weekend, supported by the NSW Police Air Wing, Rural Fire Service, State Emergency Service, Volunteer Rescue Association, mounted police and the trail-bike squad.
"We're just desperately trying to find Lily," he said.
Mobile phone data analysed
Police believe Ms Hooper had her mobile phone with her and are continuing to examine telecommunications information that could help establish where she went after arriving at the national park.
"We're also revisiting the telecommunications information that might be able to provide us a little bit of extra information," Chief Inspector Bernie said.
"We suspect Lily had her phone with her and hopefully that might provide some information if that can be activated.
"But unfortunately, that's been pretty stale since Wednesday."
The search continued from the air overnight.
"Even as late as last night we had our thermal imaging helicopter in the air trying to find her," Chief Inspector Bernie said.
He said police were still trying to establish what supplies Ms Hooper had with her when she set out.
"She left home not with obvious bushwalking equipment, but we suspect that there might have been some equipment in her car," he said.
"We're hoping that she took [it] with her. That will support her during this ordeal."
Police were unable to determine Ms Hooper's intended route, beyond the Bonnum Pic Walking Trail, and whether she reached a nearby peak.
Rugged terrain complicates search
The rugged terrain and dense vegetation are complicating efforts to cover the search area.
"It's very thick, it's very hilly," Chief Inspector Bernie said.
"There is a thick canopy which doesn't help with our aerial support and it's just rough terrain."
He said specialist Police Rescue search coordinators were directing the operation, while other police units continued investigative work behind the scenes.
Chief Inspector Bernie said getting lost or suffering an accident were among the possibilities being considered, but police remained focused on establishing Ms Hooper's movements.
"We can hopefully, as I said, find her and bring her back to her family," he said.
