Locals in Tasmania's high country are known to be fond of the saying there is "no such thing as bad weather, just the wrong clothing".
Sunny one moment, icy the next, the climate in Tasmania's central and western mountainous country has caught many interlopers out, badly.
The lucky ones manage to survive in the open against the odds or take refuge in one of a small number of shelters until help arrives.
With much cold weather still to come and a number of bushwalkers already extracted from the wilderness, Tasmania's helicopter rescue team stand ready — but warn once the island's notorious weather turns, there is only so much they can do.
This year, the Westpac Rescue Helicopter team — a joint effort between Tasmania Police, Ambulance Tasmania and helicopter contractor Rotorlift — has already been involved in more than 40 rescues across Tasmania.
In June, following the easing of travel restrictions, authorities pleaded with people to be better prepared, following a weekend of helicopter rescues — with one featuring a party of four who, police reported, had "no warm clothing, wet weather gear, or food and were ill-equipped for an extended walk and/or an overnight walk".
For Tasmania Police Sergeant Kriss Lawler, an aircrewman with the rescue helicopter team, the motivation, if not the task, is simple.
"Somebody has called for our help and our job is to go and find them," he said.
Following the activities in June and early July, the Tasmania Police officer in charge of search and rescue in western district said, in general, rescue missions "could have been avoided if people had been better prepared", and urged "anyone planning on bushwalking to check conditions before you depart and if forecast conditions are poor … delay your walk until they improve".
"While the rescue helicopter is equipped with state-of-the-art technology, there are such occasions where conditions prevent its use," Inspector Steve Jones said.
That would mean the need for search parties on foot, which he said "can obviously prolong a rescue" — and, thereby — reducing the chance of survival.
This weekend will bring with it some icy conditions.
Bureau of Meteorology duty forecaster Belinda House said Tasmanians could expect a "deep blast of cold air coming from the south", with snow expected around higher ground on Sunday and Monday.
"There will be snow to quite low levels on Tuesday," Ms House said, adding that the "freezing level" will be well below mountain peaks.
'Doors open', tried and true
As the risk of hypothermia increases, so too does the potential onset of symptoms — which St John Ambulance list as including "clumsiness", "apathy" and "irrational behaviour".
Sound decision-making — whether to take shelter and wait, or attempt to press on — can be the difference between life or death, authorities caution.
In recent times, those lost stand a far better chance due to the helicopter search teams — however, even under the guidance of specially trained and experienced pilots, the twin-engine Kawasaki BK117 is limited.
Despite an array of equipment to assist in finding and retrieving people — including night vision technology and beacon trackers — Sergeant Kriss Lawler said often it would come down to simply flying with crew members scanning the terrain for signs of human life.
"Our night vision goggles, which amplify light many thousands of times, are the most useful tool," he said, before adding "a lot of searching is done 'doors open'".
However, once the weather turns, there comes a point where a call has to be made.
The 'freezing level'
"Our single greatest challenge as a helicopter crew is the weather and the unpredictability of that," Sergeant Lawler said.
"The problems [weather] poses for people on the ground, most particularly over winter, makes it harder for us to get up into the tiers at higher altitudes
For bushwalkers waiting to be rescued, the conditions may be so bad ground personnel are stopped.
For the helicopter pilots, already battling visibility and wind, another factor is critical to whether a rescue mission can continue — explained by Sergeant Lawler as "the freezing level".
"It is the point of altitude at which moisture in the air will freeze … for us, that means any moisture on the aircraft turns to ice and additional weight."
And while "commercial aircraft can fly through clouds on theoretical on roads in the sky," Sergeant Lawler said for the helicopter crew negotiating mountainous terrain, "that's just not possible".
"It literally stop us to fly to certain parts of the state, the Overland Track is an obvious one; it sits on top of the tiers [and] we just may not be able to get there."
On July 10, the rescue team responded to a "call from lost bushwalkers" at the Tarn Shelf, in the Mount Field National Park — but had to pull out due to "weather and last light", with ground search and rescue teams completing the mission.
Sergeant Lawler said in his experience, once reached by rescuers people's shared reaction was, unsurprisingly, "relief" — but often "embarrassment".
"Setting off a locator beacon for most people is very much a last resort," he said.
"There's a few who talk about the sense of relief at the sound of an approaching helicopter."
'I wouldn't have lasted much more than another night'
One such person is Victorian man Michael Bowman, who joined the list of people who miraculously survived.
"I know the job … I had some involvement it very early on, I was in northern end of national park helping some people get out [when that happened]," Kriss Lawler said.
In July last year, Mr Bowman — considered an experienced hiker — had been walking in the Cradle Mountain Lake St Clair region when a series of mishaps almost led to a disaster, beginning with him losing his pack which contained most of his supplies and his emergency radio beacon.
Taking shelter in his small tent, Mr Bowman spent a week trying to keep warm until his tent broke and snow came in as it built up outside.
"I wasn't going to give up. If I die in the tent, I'll die in the tent, at least they'll find the body," he said after he was found.
Mr Bowman told media he had heard the sound of the helicopter and felt the rush of relief, only for them to miss him in the mist and fly away.
In the end, it was not the new technology that found Michael Bowman — it were the eyes of flight paramedic Ingrid Pajak, who spotted him from the air as he waved orange plastic garbage bags "like a windmill".
"I was just standing there … jumping up and down, then [the rescue crews] turned around and came back towards me," he said later.
"It was the happiest day of my life because as I said, I probably wouldn't have lasted too much more than another night."
Paramedics who assessed Mr Bowman, praised his actions, preparedness and "ability to cope".
"It was a remarkable story of survival, of resilience," Kriss Lawler said of Mr Bowman's ordeal.
"It goes to show that humans, if we are faced with the choice of curl up and and die or finding some solution to keep yourself together and alive overnight, the latter occurs."
And for those who do make it through the night, hopefully the sound of helicopter rotors is not far away.ABC