An Ascent of Mt La Perouse

Through a quirk in geology, the long ascent of Mt La Perouse begins atop one of Australia’s longest descents. Exit Cave worms its way 23km into the Ordovician limestone beneath these Southern Ranges. Lesser holes pepper the forest and unwary walkers in this wild area have disappeared without trace. But such chilling thoughts are soon distracted by the steepness of the uphill walk. It is all climb, through still, damp and overwhelmingly green forest. The hue is not just on the mossy forest floor or in the leaves but at every level, from roots to trunks to branches to fungi. There are fluorescent greens, sombre olives, glaucous blue-greens, lively gold-tinged greens and deep sea greens. The very air has a greenish tinge.

But thoughts of colour are unlikely to distract you for long from the relentless climb. There is nothing to do but hoist and haul yourself between, through, around and sometimes over the trees. After an hour, perhaps two, of sweat-raising effort you may sense a change in the air, and notice a change in the scale and type of trees. As you break out of forest and into a more open tea-tree and paperbark scrub, there are glimpses of the distant coast. The scent of decay-tinged damp is replaced by a sharper, cleaner air that somehow smells blue. After the shy light of the forest the sun here can be blindingly bright. If the day is calm – and sunny, calm conditions are not the norm here – you may find yourself sharing the air with a myriad flying insects: beetles, dragon flies, butterflies and a host of diptera. Most won’t trouble the walker, though march flies may show an interest in any exposed skin. As will leeches.

Although the scenery has changed, the incline of the track has not. And the more open going is countered by sections of deep mud that stand between here and the blandly named Hill 1. By the time you have trudged up to this bald, wind-battered eminence, you will have gained nearly 800m in altitude as well as a good thirst. While you take your break, the other bare hills of Moonlight Ridge are still ahead. By blunt logic these are named Hills 2, 3 and 4. But they are dwarfed by the majestic mountains that start to dominate the scene above: the Hippo, La Perouse, the Cockscomb.

Geological dramas from many eras have helped create the landscape around you. Even in (geologically) recent times – the last couple of million years – glaciers calving off Mt La Perouse and nearby peaks have dozed out deep valleys, gouged cirques, deposited morraines and left resistant rock standing above the fray. In the last several millennia, although the glaciers have gone, wind, water and ice have continued to chip away at the landscape. As you traverse Moonlight Ridge and close on Mt La Perouse itself, you climb through sedimentary rocks scraped almost clean by glaciers. First are the often softer Permian siltstones, then the more recent Triassic sandstones. Downvalley to your left Arndell Falls plunges from a cliff at the edge of a later dolerite intrusion. Although it’s tempting to leave the track here and head straight for the growing bulk of Mt La Perouse, the more oblique approach via the Pigsty Ponds is far easier. Just as you start to climb from these morraine-dammed lakes onto Maxwell Ridge, a cairned route to the left leads you up the long humped slope to the remarkably bare and flat-topped “peak” of Mt La Perouse.

The sandstone here was laid flat on a sandy plain, and despite all the ructions of the last 200 million years, remains remarkably flat to this day. If you were inclined to celebrate your ascent with a football game, the top of La Perouse would not look out of the question. But the winds that blast here most of the time, and prompted walkers to build a massive (and sheltering) summit cairn, would rule out most forms of football most days of the year. A quick and grateful look towards the indented coast; a peek over the edge towards the classic cirque lakes called Swallows Nest Lakes; an admiring photograph over the striking doleritic Cockscomb; a quick celebratory drink; these would be the best you could ask of La Perouse, even on a good day.

Witnessing A Coup

[Written during a visit to Alaska in 2005]

Many of Tasmania’s most vivid landscapes have been bequeathed us by ice. Yet even a deep and prolonged association with both the fact and the landscapes only partially readied me for the drama of seeing a working glacier. The U-shaped valleys of Tasmania’s Lake Judd have a clean elegance, while the steep sides of Lake St Clair wear a forest-fringed softness. Even the vertiginous cirque walls of Lake Huntly and the sharp aretes of Cradle Mountain have a finished look, as though the ice has stepped back to admire its work. All of Tasmania’s glacial landscapes seem to mix even their most abrupt shapes with a sense of mellowed age, a vintaged wine whose astringent elements have been tempered through time in oak or bottle.

While flying over the altogether younger ice-fields and glaciers of Baranof Island in south-east Alaska, there was still a white-wedding aura about the uncomplicated virgin white of the stunning scene. Snow white purity dominated, with the somewhat dowdier peaks and lakes merely making up the wedding party. Given this gentle introduction – and my own Tasmanian conditioning – I was ill-prepared for the shot-gun wedding that is the South Sawyer Glacier. One of Southeast Alaska’s many sea-level or tidewater glaciers, South Sawyer extends more than 30km to the sea from the 2,500 metre mountains and ice fields of Canada and the Tracy Arm – Fords Terror Wilderness. The glacier guards the landward end of the vast Tracy Arm fiord, once a glacial valley itself.

The day of our visit is a rare and gloriously blue-skied Alaskan day. But it is the blue of the glacier that initially steals the scene. This is no blushing white glacier, nor even a pale, powder blue one. John Muir truly called it a “quick and living blue”. South Sawyer presents a huge rough-cut maw to us across the terminus of Tracy Arm, grinning with deep cobalt ice-teeth. If at first all seems silent, we soon discover otherwise, for this is no stately and static set-piece. Both teeth and ‘food’ are in motion the whole time we are there. Crashes and clashes of rock, ice and water are seen and heard all around. Meltwater shifts great quantities of rock and silt from the steeply enclosing walls and from beneath the glacier, pouring them into the water in torrents or loosening them for gravity to take its turn. Boulders tumble with loud, echoing thuds. Yet to the eye – fooled by the clear air and lack of vegetation for scale – the boulders look like mere clods of earth, fraying into fragments as they fall. With slow, chaotic regularity bergs of varying size slice off the glacier’s face, again seeming mere slivers until the sound reaches us with a thunderous roar. To call these juddering collapses ‘calving’ – a term that for me has gentle bucolic associations – seems to down play the rugged reality of a birth under the pressure of both gravity and the bullish weight of ice pushing from behind. Or is my perspective overly urban and masculine? Perhaps giving birth – even bovine birthing – really is as noisy, dramatic and messy as this.



As we watch and listen, some of last week’s bergs squeeze quietly past us. It is like rubbing shoulders with the ancients. Each luminous blue beast may be literally prehistoric, made up of compressed snow that fell many hundreds of years ago, and has moved from mountaintop to sea at as little as 20 metres a year. We had passed their brethren on the way here, all blue and bobbing in the sun, but growing imperceptibly smaller as they made their relatively hasty way to the sea and oblivion.

In fact glaciers are no drop-in-the-ocean. They hold over 2% of earth’s total water, oceans included. And around 75% of the planet’s fresh water is held in glaciers. Were all of these beasts to become extinct, sea level rise would be catastrophic. Each ancient berg also carries small loads of silt and dust, some stolen from surrounding rock, some sprinkled on them from the heights, some added by short-lived streams that flow onto the glaciers in summer. All will be added to some far future sedimentary formation, when even the unthinkable depths of Tracy Arm will be forgotten, and a new landscape will joust with ice, rain, heat, fracture or whatever else is thrown at it.

But the present action isn’t only mineral. Animal and vegetable stake a claim here too. On the congested ice dump beneath the glacier’s snout hundreds of harbor seals (Phoca vitulina) dot the ice. With the temporarily solid ice preventing orcas from attacking, the seals loll insouciantly in the sunshine. It must feel quite the opposite of skating on thin ice – at least until hunger forces their next fishing trip.

From the surrounding slopes alder, hemlock and spruce watch and wait as the glacier retreats. In a mere dozen years it has retired hundreds of metres. Eventually, even in this dramatically steep terrain, there will be land ready for colonising. Others may be the first, but the conifers will surely follow. At the Mendenhall Glacier on the outskirts of Juneau, the glacier’s retreat has been systematically observed for well over a century. The Visitor Centre, high above Lake Mendenhall and several hundred metres from today’s glacier, was built where the glacier had been active as recently as 1935. Where once ice went unchallenged, there is now established coniferous forest. An ordered and predictable succession of growth has been noted, with lichen doing its rock-breaking, soil-producing work first. This is followed by pioneer species such as willow, fireweed and alder. Finally within 70-80 years the conifers start to predominate.

A day in the company of glaciers has me comparing history with geology. We may read blithely of a coup that replaced King A or President B, with years of peace (or otherwise) following. So too we may study geology and read mechanically of the epic landscape-altering work of glaciers. But seeing the violence and mayhem of a glacier up close seems to me like witnessing a coup. History judges a coup by its outcome. So too will geomorphology judge a glacier by its resulting landforms. But what a privilege, albeit a dangerous one, to be there for at least a small episode of this earth coup, and to see first-hand the processes that once shaped so much of my island home, Tasmania.