Without doubt Loch Lomond Mountain Rescue Team members Martin McCallum and Ian Dawson would be considered experienced climbers.
Martin is Lomond's deputy team leader and has tackled peaks in the Alps, Tatras, Yosemite, Joshua Tree and Ouray, while Ian has been walking and climbing for more than 20 years in the UK, Europe and South America.
But here Ian, a professional photographer, reveals how North America's highest mountain Denali tested their skills, fitness and determination to the extreme.
Breathe, kick, step, rise.
The slow rhythm becomes as hypnotic as the long progress up the deep blue ice of Denali's upper headwall.
The expedition required endurance and experience
Muffled deep within thick layers of clothing, hearts pounding, the whistling draw of unsatisfactory breaths, merging sharply with the metallic thud of crampons and axes.
Our previous days have been spent watching specks of black, stark against the vast white face, slowly gain human shape through endless hours of toil, descending from high places.
There is a welcome simplicity to each day's routine. Get from A to B.
It is as simple as the preceding months preparations for the expedition to Denali were complex.
Sitting with my climbing partner, Martin McCallum, poring over minutiae of equipment details on the warm banks of Loch Lomond seems a world away.
Two planes and a three-hour shuttle brought us to the half-a-horse town of Talkeetna, Alaska.
Our first glimpse of Denali - America's highest mountain at 20,320ft (6,193m) - some 60 miles (96km) hence, takes your breath away - filling an impossibly large amount of sky.
Pushing through the doors into the Talkeetna Air Taxi office dispels any thoughts of lethargy. 'Ready? We're going now!'
A mass of 250lbs (113kg) of equipment is jammed into every available space of the light plane.
Soon the throaty roar of the Beaver can be heard clipping the tree tops of the Alaskan bush.
The bush pilots maintain a runway on a fork of the main glacier.
Landing lightly on skis in the temperamental snow the rigmarole of checking in, arranging packs and sleds with nine stone of food, fuel and shelter each is dealt with quickly to escape the melee.
Shouldering packs and clipping into sleds marks the start of a week of heavy, mindless toil in the white, mile-wide expanse of the lower Kalhiltna Glacier ascending 14 miles to the 14,200ft (4,328m) camp.
More than 1,000 climbers attempt Denali during the brief season from May to July every year.
We face late afternoons under the grumbling summits that hang over the glacier.
The heavy snow fills yawning crevasses, making the glacier safe to walk on, turning the forked valleys into collecting bowls for vast avalanches that the afternoon sun peels from skyward looking faces.
We find the East Fork of the glacier has been decimated by avalanches.
This renders our intended route of the West Rib at best foolhardy.
So we adapted our plans.
Making for the West Buttress the gusting winds become steadier and stronger as we slowly gain height over six days.
Edging into the international snow village of the Genet Basin we scatter, scavenging for a half-made home.
Excavating a camp from the virgin snow can take hours.
As it is, our second-hand home takes four hours of hard labour, sawing blocks through Styrofoam snow to fashion walls capable of withstanding Denali's worst excesses.
Excessive they can be - the lowest temperature recorded here stands at -148 and winds far in excess of 100 mph.
Our first night is a chilling introduction to how we'll spend this trip - battling the strong arctic gales, our tent contorted by the 'Polar Express' winds that gathered momentum with the sound of an speeding train.
Tightened fingers gripping the apex of the tent couldn't prevent the violent vortex from buckling our fragile home into a grotesque shapes.
The morning silence brings a surrealism as it is broken by 'Bill and Ted' our neighbours. 'Whoah Dude. That's like a total trip-ender maaaan'.
Martin, poking his head from the cocoon of the tent, looks over the demolished snow walls and the shreds in the tent fly.
Denali, as we will discover, is as much about adaptability and ingenuity.
Dental floss, seam sealant and cannibalized nylon bags and a needle help reconstruct a serviceable home.
The wind abates but leaves in its wake days of falling snow. This allows for recuperation and time to carry out repairs.
Such perilous conditions sadly saw the loss off two of America's leading female alpinists.
The military flew in a double bladed Chinook to airlift a hold full of casualties - broken limbs, frostbite and severe altitude sickness that eventually took the life of a climber on the headwall.
Our quietly confident Slovenian neighbours succumbed to the lure of the summit.
Called on through the freezing air, devoid of food and water, they were buoyed by their success on their return.
'You drink with us,' they said, passing a plastic bottle of Australian Red grasped by blistering fingers.
We were at that moment preparing our own longed-for attempt on the summit.
A feeble, tinny beep is coming from an alarm somewhere in the haven of my sleeping bag.
It is snowing inside.
My exertions have dislodged a thick layer of hoar frost from the tent roof, which lightly showers down on us both.
As I open the tightly cinched neck of the bag the sharp cold cuts through me.
The temperature is reading -35. Martin coaxes the stove into life. We are against time - a week-long Bering Sea storm is due in under 24hrs.
I constantly tap thumb to fingertips and toes to boot inner. When is cold too cold?
The double insulated metal of axes are drawing heat from the palms of triple gloved hands and toes are numbing as our boots thump into the headwall ice.
Reaching the airy ridge is invigorating, the exposure and the chill air reveals the vast panorama around.
Step by step, each is deliberately placed, tested and weighted, conscious of the 3,000m (9,842ft) of space beneath me.
The perverse equation of altitude where pace, and the ability to keep warm, decreases as you forge ever higher into the thinning air.
Shooting pains through my toes begin to seep in a numbness that would not shift.
Stopping to eat and drink insulated flasks and gel foods stored next to my chest I find each frozen to the core.
One frame from my camera is enough exposure for its oil to freeze solid.
Clearing my throat, spit freezes before it leaves my mouth as an icicle to be snapped from my bottom lip.
Months of hard graft have brought us to this point. But in contrast, the simple decision is made in just seconds - knowing the serious consequences of making the wrong choice right now.
Of the few who chose to reach the summit that day all suffered serious frostbite the unluckiest losing 10 fingers and 10 toes.
Climbers on expeditions to Denali
As the mercury flashes -50 there is no hesitation in turning around and starting the descent home from 17,000ft (5,181m).
Days later as I stand back in the technicolour surroundings of a Talkeetna gift store I know I made the right choice.
The Slovenian who was so eager to share his celebratory drink with us back out on the mountain has made it back to safety too.
With watery eyes, he stutters out the words: 'You must look, look here,' as he slowly strips off the snowy white lint gloves that shield his dead, black fingers.