A 23-year-old Canberra cross-country skier missing in the NSW Snowy Mountains has spent two nights in freezing conditions.
Police say the man last made contact with his family about 10am on Saturday, sending photos and "showing him in good spirits and in the snow".
He told them he planned to ski the back country of Kosciuszko National Park and police found the man's car at Guthega car park later that day.
Police said they left notes on his car in case the man returned to it.
The man's mother raised the alarm on Saturday night when he failed to return or make further contact with his family or friends.
He has not answered his phone or operated a personal locator beacon, which family believe he took with him.
The experienced cross-country skier is believed to be carrying limited day supplies and adequate equipment for back-country conditions.
Police believe the skier, whose family have requested he not be identified, is in a remote part of the Snowy Mountains, Queanbeyan Police Station Superintendent John Klepczarek said.
"The family and friends have expected him to make contact and definitely be back by now, so as a result there are concerns," he said.
"He's equipped to stay overnight, so we have confidence in his ability in that regard. We're just hoping that something hasn't happened along the way."
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A search involving specialist police from the Alpine Operations Unit, State Emergency Service and National Parks and Wildlife Service was underway on Monday. PolAir was expected to be on site on Monday at 12pm.
Police said good friends of the skier have pointed them to popular remote areas the man may have frequented.
"We're focusing in that area. We have a lot of people, including some of his friends, on foot, walking in some of the remote areas," Mr Klepczarek said.
"There's an area at the back of Guthega which we are sort of concentrating on, but it's all that high country, and that's why we require some aerial support to give us a much broader range.
"Up in the high country there's numerous possibilities, but we're hoping it's as simple as his mobile phone's gone flat, maybe he wanted just to stay an extra night ... it's not right to speculate what might happen, we're just focusing on positives."
Emergency services have also checked many of the popular huts used by skiers and hikers who get stuck overnight.
Mr Klepczarek said the skier was experienced enough to create his own shelter and had prepared more than most skiers or hikers who go missing.
While Snowy Mountains weather conditions were reportedly good on Monday, Mr Klepczarek said alpine conditions could change at any time.
"That's why we've gone quite hard this morning, with the number of people looking for the missing skier," he said.
"We have quite an experienced and extensive team. So the best possible searchers we have for that area are up there.
"I couldn't ask for anyone else to be up there at this moment."
Temperatures on Monday are predicted to range from minus two degrees to three degrees.
There have been 12 people reported missing in the snow this season.
Staying safe outback skiing or snowboarding:
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