Eight teenagers and three teachers rope up together for safety and dig in with their ice axes as they travel across the snow-covered Alaskan wilderness.
Nearly 40 glaciers flow out from the Harding Icefield, a vast landscape about a hundred miles south of Anchorage.
On the first stage of their journey, the group spots a lone black bear. But once they arrive up on the Harding Icefield in Kenai Fjords National Park, they don't see another living soul for nine days.
Banchory Academy's Alaska Expedition 2012 is a remarkable trip for these six boys and two girls. For some, it may inspire a lifetime of exploration and excitement.
Few state schools organise and lead expeditions such as this independently, but these teachers are highly experienced mountaineers, keen to share their skills and appetite for adventure.
The expedition isn't for lightweights. They all carry 60-pound backpacks with tents, stoves and enough food for nine days up to the icefield to set up camp. It's an ascent equivalent to climbing Ben Nevis - and they do that twice over two days. "It was the whole day - six hours up and four hours down and then back up next day," says 17-year-old Henry Rowett.
As well as strength, they need stamina and guts. There is no shortage of material for a risk assessment form in this landscape. There is no mobile signal, so the team carries a satellite phone, emergency beacon locator, an avalanche transceiver and bear spray to fend off any who come too close. Oh and no need for soap or shampoo - no showers and no loos.
For Ailis McQueen, 17, this adventurous rite of passage has become a family tradition: "My oldest brother did the first Alaska trip with the school and my second-oldest brother did a trip with the school to Siberia. After seeing and hearing about their experiences, I felt it was something I wanted to do as well," she says.
The youngest team member, Alastair Willan, 15, is following his sister's footsteps: "She went to Siberia and said it was really good and a fantastic opportunity," he says. "I'm not really looking forward to the poo bag, though."
No one is. But the park's "Leave No Trace" policy means the team leave the icefield in the same pristine condition as they find it. So they will take turns carrying their collective waste back downhill at the end of their visit.
Banchory Academy runs expeditions like this every couple of years, led by depute head Graham McDonald. He taught geography after running an outdoor centre at Ballater for 20 years and recently stepped down after 40 years as a member of the Braemar Mountain Rescue Team.
He has led young people on journeys all over the world, to places such as Siberia, Africa, Asia and Alaska over the past 30 years. He is accompanied by another two highly experienced climbers - guidance teacher Niall Ritchie and Jas Hepburn, who teaches at Grantown Grammar and studied PE with Mr Ritchie at Jordanhill.
Together, the three men have over 100 years' international mountaineering experience - a statistic they no doubt calculated on one of these long nights on the icefield, when the light never dies.
"This is real mountaineering in a wilderness environment - this is not hill-walking that you'd get up to in Scotland," Mr McDonald explains. "This is proper full-on mountaineering with all the attendant hazards."
Just after Easter, teachers get an idea how pupils will handle themselves, during a snowy training weekend up Lochnagar. "You need to be comfortable on snowy and icy ground and you need to be reasonably competent with rope work and these are all skills we develop with the youngsters when we're away," he says.
"You need crampons, ice axes - everybody will have a mountaineering helmet on and a mountaineering harness and all the time we move on the ice we will be roped up," he adds, as they make final preparations for the expedition.
The teenagers research the trip, which begins with flights to Seattle and on to Anchorage. Once the expedition starts, they each take charge as leader for a day. In-house planning has advantages. "The first benefit is financial. But the second and most important is that the youngsters really have a handle on what's going on," the depute head says.
The basic cost for each pupil is pound;2,500 - cheaper than using private companies to plan and lead. "Pupils are really planning the trip. We're in the background, offering advice and guidance as we can, using our years of experience to help them," he adds.
This means pupils are learning the details - that they need 300-500 calories an hour to keep energy levels up, and can plan their shopping list for arrival in Alaska accordingly. They are camping for most of their 17-day trip and they know food will be basic and personal hygiene low priority on the icefield.
But what seems to take them by surprise is the sheer beauty of the place. "It was incredible," says 16-year-old Jamie Brown after their return. "Just something I've never experienced because it was so empty. There's nothing there - no civilisation - nothing that's living, just mountains.
"You're just away from everything - it's kind of spiritual in a way, you can think of it like that. Not in a religious way, but you think about things out there because there's no technology and no connections to the outside world. It's just you there."
Everyone looks tanned and healthy after daytime temperatures in the sunny 30s on the ice. The nights are colder though - below freezing, even in late June.
"Just walking across the ice was a completely different experience to anything I'd ever done before - so that was exciting," says Henry Rowett, 17. "We didn't need the crampons because there was so much snow. It's really different - just looking around and seeing white as far as you can see."
His friend Jamie Brown, 16, says taking all the gear up on to the glacier was difficult, but once they reached the icefield there were new challenges. "You have to rope up in case of crevasses - so if you fall down a crevasse, you're all roped up. We all roped up and then you dig your ice axe in, to prevent anyone falling through it."
It was on the way up to the icefield that they saw the black bear. "There are no polar bears in Alaska, it's just grizzlies and black bears," Jamie explains. "Black bears aren't too bad, because they're used to seeing humans. But grizzly bears can be a bit unpredictable - luckily we didn't see any grizzlies."
"We were walking up the hill and it was just like eight metres away from us, in the bushes walking up," says Jo Lane, who has just finished sixth year. "I like bears - they're my favourite animals, so I was excited. And it was a lot smaller than I thought it was going to be - it was cute."
The high point of the trip came when they were exploring the icefield. "We were climbing the nunatak, which is a mountain on the ice," says Jo's friend Ailis. "It was incredible - there wasn't a cloud in the sky. It was completely blue and all you could see was a vast distance with all the other nunataks around. None of us spoke. We were all just sitting on the top - that was the best moment. It was amazing."
The adventure is life-changing for some of these teenagers: "It's just being aware that there are places like that still left on the planet, complete wilderness for miles - it's pretty awesome," says fifth-year pupil Angus Hart.
Paul Sweeney, 16, now has an appetite for more travel: "I think I would be more up for doing those things by myself with a few friends, instead of going with a guided tour. It's given me the confidence to just go out and enjoy life."
A daily diet of porridge and freeze-dried food like pastas with sauce has kept them going better than they expected: "The food tasted good because we were all really hungry," says Callum.
Back off the icefield, in the nearby fishing town of Seward, they enjoy their first hot showers in nearly two weeks and tuck into plates of halibut and chips.
As their journey draws to a close, Paul Sweeney says his thoughts turn to family and home comforts. "I texted them when we were back in Anchorage, just to let them know I was off the ice and find out what was for tea when I get back."
After Banchory Academy's last expedition to Alaska, two pupils began planning another adventure immediately they returned. "Two of the group went off to climb Kilimanjaro within six months as 17- and 18-year-olds, which is pretty impressive," says mountaineer and teacher Niall Ritchie, who had been to Alaska with them.
It's evidence just how much confidence this school expedition gives pupils and how their independence has grown. "They are not spoon-fed and I think it's really good experience for them," he says.
"It's about developing the soft skills that are important in everyday life now," adds colleague Graham McDonald. "It's about teamwork, it's about leadership, it's about showing commitment."
They are conscious of the hazards and spend time preparing and training pupils before and during the journey. "You've got crevasses, potential snow slips, potential rockfall, potential foul weather - thunder," Mr Ritchie says. "There's no real quick getaway and there's no real rescue service, albeit we had satellite phone and safety equipment such as avalanche transceivers."
Happily everyone has returned home safely and - for the first year - without a single blister. Despite the century of mountaineering between them, the teachers agree that climbing to the top of the nunatak was "the best day ever".
It's almost midnight by the time they get back down the hill and prepare their dinner. But Niall Ritchie says the light was still perfect: "In an alpine glow with a rosy pink tinge on the mountains and a moon behind it. It was unbelievable."
Photo credit: Niall Ritchie