The imprints from this period of intense glaciation are today some of the icons of the South Island landscape: large terminal lakes on the eastern side of the alps, deep valleys carved into solid rock, soaring peaks unlocking the sky.
Two of the larger lakes left behind by the retreating ice are Lake Wakatipu and Lake Wanaka, and the tramp over Cascade Saddle is a journey between their headwaters, traversing the remnants of this ancient glaciation.
The trip begins on the Wanaka side in the Matukituki River valley: a popular walking valley and a remarkably easy way to experience some of the Southern Alps' most impressive mountains.
During the two-hour walk to Aspiring Hut, the beauty of Mount Aspiring National Park slowly unfolds.
Sheep and cattle graze the open river flats lower down, but your attention is gradually drawn skywards as progressively bigger mountains reveal themselves.
Arriving at Aspiring Hut often has a sociable feel about it, the hut being a common meeting place for trampers and climbers as well as those who simply want to walk up for a picnic lunch.
The historic stone-clad structure is beautifully maintained and the hut is fully serviced, including a telescope (used mainly for spotting the progress of climbers on Mt Aspiring) and a small supply of reading material for those wet weather pit days.
Increased use in the past 10 years has meant the addition of flush toilets - sacrilege to those who like the rustic nature of long drops, but at least this new luxury has been faithfully clad in river stone to blend in with the existing architecture.
Built over a number of years by volunteers from the Otago section of the New Zealand Alpine Club (NZAC), Aspiring Hut was opened during the Easter holidays of 1949.
By Christmas, it had become the temporary base for a group from the National Film Unit, who had turned up en masse to film an ascent of Mt Aspiring.
The group included celebrated photographer Brian Brake, the artist John Drawbridge and a young, 24-year-old poet - James K Baxter.
The film was never finished, largely as a result of the stormy weather, but the experience made a lasting impression on Baxter and became the source of inspiration for one of his most well-known poems.
Poem in the Matukituki Valley begins with a reflection on the simple pleasures of the area from a perspective of one half-aware.
As the poem progresses, Baxter's reactions become more deeply layered until, at the end, awareness arrives in the form of the landscape posing questions the writer would rather avoid.
Sky's purity; the altar cloth of snowOn deathly summits laid; or avalancheThat shakes the rough moraine with giant laughter;Snowplume and whirlwind - what are theseBut His flawed mirror who gave the mountain strengthAnd dwells in holy calm, undying freshness?While the mountains are seen to mirror God's greatness, the final verse warns how the mirror can also be turned to reveal humankind's great failure - city life and the deathly insulation that accompanies it.
The final stanza is partly mocking of those too completely taken with the urban environment, yet also confesses how most people are now only visitors to the eternal world and, after a couple of weeks at the most, once again turn their backs on wildness for the supposed safe mediocrity - the gentle dark of civilisation.
Therefore we turn, hiding our own soul's dullnessFrom that too blinding glass: turn to the gentleDark of the human daydream, child and wife,Patience of stone and soil, the lawful cityWhere man may live, and no wild trespassOf what's eternal shake his grave of time.
From Aspiring Hut, it's a long, two-hour trudge up through beech forest to a campsite just inside the bushline.
Unfortunately, there is only space for two tents and it's 20 minutes back down the track to water.
It is, however, a useful site for breaking the climb into two and avoiding the crowds which can sometimes congregate back at Aspiring Hut.
Fifty metres further on, the forest ends abruptly and the route follows the general line of a spur, with brightly coloured waratahs marking a cunning line through the steeper sections.
For nearly 600m the trail ascends through a textbook progression of alpine tussocklands.
From a distance, tussocklands can be something of an optical illusion; that is to say they sometimes all look the same! But there are in fact many species of tussock on mainland New Zealand, and Mount Aspiring National Park contains some of the most impressive and distinctive examples of these alpine ecosystems.
For the first few hundred metres after leaving the tree line, the taller tussocks (sometimes reaching up to one and a-half metres in height) dominate the environment, most commonly the narrow-leaved tussock (Chionochloa rigida) and the mid-ribbed tussock (Chionochloa pallens).
At this altitude, in early December, there are often delicate giant mountain buttercups (Ranunculus lyallii) growing among the tussock, and in places tramping can become something of a waist-high wade through vegetation.
As the track ventures higher, shorter snow tussocks take over, and the curly ends of Chionochloa crassiuscula provide essential handholds for negotiating the steeper ground.
It is a common occurrence in this terrain to ascend or descend a tricky section only to look back with a quiet shudder, imagining what the going would be like without these hardy plants to hold on to.
Just before the 1800m ridge crest, the track heads out to the left (true right) on to easier ground before crossing back to the right again on to one form of tussock trampers hold mixed feelings towards.
On flat terrain carpet grass (Chionochloa oreophila) is a pleasure to walk on, but on steep ground its short, slippery nature can be something of a death trap.
In the wet, only the foolish would venture on to this sort of ground unprepared; in desperate conditions even the confident will strap on crampons for extra traction.
The wise wait until the rain stops and dry conditions prevail.
After a short, steep scramble up the final few metres, we finally emerged dripping with sweat at the old pylon point erected in the 1950s to guide trampers to this spot.
The views from here are sensational.
I had recently re-read Douglas Adams' book Last Chance to See, where he described a vista in Fiordland as the sort which makes you want to break into a round of spontaneous applause.
Cascade Saddle provides just such a vista, due in no small part to the way Mt Aspiring (3027m) anchors the eye, richly deserving its Maori name Tititea - "the glistening peak".
I sat catching my breath and looking at the view, the composition of which had me lost for words, before breaking into a round of spontaneous applause.
A perfect example of a glacial horn, Mt Aspiring's distinctive symmetry has been carved out by the action of three glaciers working back to a common point.
From the saddle, the visible ice field is the Bonar Glacier.
On the other side of the mountain the mighty névé fields of the Therma and Volta glaciers complete the sculpting trio.
Sitting on this ridge-top perch in the morning sun, I found myself idly wondering what sort of emotions the Welsh climber Bernard Head must have experienced when he reached this point as part of the first recorded climb up to Cascade Saddle in 1911. (He named the saddle after the large waterfall which cascades from it in two giant leaps into the Matukituki Valley.) Head, along with his New Zealand guides Alex Graham and Jack Clarke, had made the first ascent of Mt Aspiring two years earlier on November 23, 1909.
Tragically, like thousands of others, he was not to survive the horrors of Gallipoli.
It would be hard to imagine two more different experiences for a person to go through in such a short time span, and this sad thought tempered my own initial joy at reaching the high point of the track.
From the pylon, the route sidles down a couple of hundred metres into a creek draining the slopes of Mt Tyndall, and then up a slight incline to an extensive tussock shelf, which leads around to the low point and the saddle proper.
The abundance of water here provides an ideal habitat for the large white-flowered buttercup (Ranunculus buchananii) and streamside profusions of marsh marigold (Caltha obtusa), both flowering in early January.
Later in summer, extensive clusters of snow marguerites (Dolichoglottis scorzoneroides) put on a showy display, making a friendly foreground to the backdrop of peaks and glaciers.
The smell in these alpine gardens is usually the result of a number of species of Anisotome (members of the carrot family), which have a sweet, herbaceous fragrance.
Descending around to the low point of Cascade Saddle, the Dart Glacier comes into full view.
In the last 50 years, like many glaciers in the Southern Alps, the Dart has retreated at an alarming pace, the current rate being around 50m a year.
Glacial recession is one of the many indicators that climate change, in the shape of global warming, is upon us.
There now seems little debate that the steady rise in mean annual temperature has resulted from the industrial revolution and the accompanying increase in burning carbon products.
Somewhere between 1935 and the 1960s the retreat of glaciers in the temperate zones of both hemispheres rapidly accelerated.
And the sobering reality is that humans have already pumped enough carbon dioxide into the atmosphere to keep the globe at its new, warmer temperature for the next 400 years.
In other words, even if we all stopped driving cars tomorrow it would be like a Band-aid on a gushing artery.
As a smaller glacier, the outlook for the Dart is not good, and if the current rate of recession continues it will be gone in another 80 to 100 years.
If you think this is being a little alarmist, or that glacial recession doesn't affect us in any way, take a seat in the tussock and look out on to the Dart Glacier.
All that frozen ice before you is a small part of the complex energy balance which keeps the South Island ecosystems working.
Glaciers store energy in the winter and release it in the summer.
Global warming means much more energy will be lost each winter as warmer rains corrode the glaciers instead of preserving them.
In time, the balance will be changed to such a degree that the hydro lakes and farm irrigations further down will have too much water when they don't need it and not enough when they do.
Obviously, this is putting it simply, but it is very naïve to think that altering the climate and the energy cycles of the glaciers will not affect our daily lives in far-reaching ways.
The descent from the saddle into the Dart Valley is straightforward and begins by traversing along a tussock shelf between two vast sloping plates of rock: one dropping down at 30 degrees into the Dart Glacier, and one above which stretches up at the same angle for a few hundred metres on to the Mt Anstead ridge.
The current terminus of the Dart Glacier is quickly reached and here the landscape is both desolate and dynamic.
The Dart River gushes forth from the snout of the glacier, weaving its way among kettle tarns and recently deposited glacial till before curving away down the valley.
The impression is of a bleak landscape in a constant state of change.
The trail from the terminus is well marked with an assortment of rock cairns.
On the descent from Cascade Saddle these cairns have become something of a sculptural art form with passing trampers making impressive attempts to imitate the work of New Zealand sculptor Chris Booth.
On this part of the track they seem to appear less out of necessity, for the track is fairly obvious in most places, but more from a cheery desire to celebrate that the end of a long day is near.
By the time the track reaches the point where the glacier terminated in the 1850s, nearly 5km from its present terminus, the landscape has a more permanent feel and the old moraine flats underfoot are covered by a mosaic of mosses and small shrubs.
Dart Hut is located just inside the forest across the Snowy Creek swingbridge at an altitude of 900m.
The tree line here is 100-200m lower than many parts of Mount Aspiring National Park, largely due to the colder air draining down from the Dart Glacier.
From Dart Hut there are two options for finishing the journey.
The easiest is to simply continue on down the Dart Valley to Daleys Hut and then on to the Paradise road end.
The Dart Valley has superb beech forests, which support an encouraging amount of native birdlife: there is a good chance you'll see the rare yellowhead or mohua (Mohoua ochrocephala), flocks of tiny riflemen, kakariki and the South Island robin.
But if you still hanker for the tops and the weather is good, a more interesting route is to head up Snowy Creek to Rees Saddle and then down the Rees Valley to the Muddy Creek road end.
The climb to Rees Saddle begins by first re-crossing the swingbridge and then climbing up through low scrub beside Snowy Creek.
About halfway to the saddle the climb flattens out and a second swingbridge (which is removed each winter) crosses back to the true left of the creek.
It is about here that you briefly leave Mount Aspiring National Park.
For reasons that can only be clear to map makers and bureaucrats, Rees Saddle was omitted from the national park.
The climb on to the saddle is completed after an hour-long traverse high above a spectacular gorge that Snowy Creek has cut out of the bedrock.
At 1441m, Rees Saddle is slightly lower than Cascade Saddle, but still provides spectacular views down into the Rees Valley and northeast on to Headlong Peak.
From here, the remainder of the tramp is all downhill and a poled track leads off under a set of cliffs before flattening out into an easy stroll down a basin.
Just below the saddle keep a lookout for mountain weta.
There are a number of species which live in the alpine regions of the Southern Alps, and the population here has pronounced stripes and reddish margins - a local variation on the more common larger type of alpine weta (Deinacrida connectens).
Just as the vegetation changes to a mixture of tussock and subalpine shrubs, the track sidles out high above the headwaters of the Rees and slowly bends around a corner until, 40 minutes before the hut, the east peak of Mt Earnslaw appears for the first time.
A giant of a mountain, Earnslaw was one of the first major peaks scaled in the Southern Alps when Harry Birley climbed it solo in 1890.
Although not technically difficult, Mt Earnslaw dominates the western end of Lake Wakatipu and continues to attract climbers.
Shelter Rock Hut, which is composed of one recently renovated hut and a second newer building with two bunkrooms, is located in an idyllic spot just before the tree line.
It is a peaceful place and ideally suited to sleep the sleep of the dead.
The next day, the six-hour walk through valley forests and along grassy flats to the road end will seem a long way from the stark landscape of the Dart Glacier, but take a longer look; the signs of a once mighty glacier are still present.
If you go ...
Cascade Saddle,
Mount Aspiring National Park
Length: 50km.
Time required: four to five days.
Nearest towns:Wanaka and Glenorchy.
Best time to walk the track: Late November to April.
Fitness: Good fitness required.
Maps: (NZMS260) E39 Aspiring, E40 Earnslaw; (Topo50) CA11 Aspiring Flats, CA10 Lake Williamson, CB10 Glenorchy.
The journey over Cascade Saddle is normally started from the Lake Wanaka (Matukituki Valley) side for the simple reason that it is the quickest way on to the tops. The route is well marked with cairns and poles but still requires moderate route-finding ability. There are several excellent places to camp if the weather is fine, and a well-maintained network of huts.
Aspiring Hut is run by the Department of Conservation for the New Zealand Alpine Club and is not covered by a back-country hut pass. The hut fee is $25 a night during the summer, and $20 during winter. An $8 fee applies for camping near the hut.
A warden is present between November and April, and fees are either paid to the warden or the local Doc field centre. All other huts are operated under the back-country hut pass, but it is advisable to carry a tent in summer because Dart Hut and Shelter Rock Hut are often busy.
Above the bush line, the route from Aspiring Hut to Cascade Saddle is steep and should be avoided in wet or windy conditions, and especially if it has recently snowed. There have been fatalities there.
Early in the season, crampons and ice axes may be necessary for a short section of snow before the pylon. The Matukituki side of Cascade Saddle is avalanche-prone and not recommended in winter or early spring.
When descending to Dart Hut, the initial traverse from the ridge to Dart Glacier is above 1500m and exposed to the weather. There are two flood-prone creeks between the Dart Glacier and Dart Hut - this section is not an all-weather route.
A shuttle service operates between Wanaka and the start of the tramp in the Matukituki Valley. At the Glenorchy end, a transport service operates to the Muddy Creek road end, and on the Dart River a jet-boat service can be organised to pick trampers up from Sandy Bluff. Check with local operators for the pick-up times because you may need to book in advance.
Approximate track times (walking from Wanaka to Glenorchy)
Raspberry Flat carpark to Aspiring Hut (38 bunks)9km, two hours.
Aspiring Hut to Pylon (1800m)5km, 4-5 hours.
Pylon to Cascade Saddle (1510m)2km, 1-2 hours.
Cascade Saddle to Dart Hut (32 bunks)9km, 4-5 hours.
Dart Hut to Shelter Rock Hut (22 bunks)9km, 5-6 hours.
Shelter Rock Hut to Muddy Creek car park16km, 6-8 hours.
Information
• Department of Conservation, Wanaka area office, Wanaka. Phone: (03) 443-7660.
• Department of Conservation, Queenstown Visitor Centre. Phone: (03) 442-7935. Email: queenstownvc@doc.govt.nz
- Rob Brown
