Driving the Carretera Austral

I pressed my nose against the plane window and peered into a different world. Shrouds of snow lay over the uppermost peaks of the Andes, spilling on occasion down serrated flanks like icing dripping from the rim of a cake. Below the snow line the mountains folded in colourful layers of mauve and mahogany, their steep sides lined with tributary scars as if raked by the claw of a primeval deity. This was northern Patagonia, the most rugged and remote part of continental Chile.

As we began our descent into Balmaceda airport, the thoughts of the group turned to the winding road ahead. Waiting on the tarmac, near the rusting hulk of a burnt-out fuselage, were two Toyota pick-up trucks and a set of directions for the Carretera Austral.

Described by one local as "the only good thing that Pinochet did for Chile", the Carretera Austral, or Southern Highway, is a largely dirt road that rumbles for a little over 1,200 kilometres from Puerto Montt in the Chilean Lake District to the isolated village of Villa O'Higgins on the edge of the Southern Patagonian Ice Field.

From Balmaceda we ventured south to Villa Cerro Castillo, where we waved goodbye to the comfort of asphalt. From here on in the road was a river of ruts and ridges, dust and loose gravel, with jaw-dropping views around every slippery corner. Giant Chilean rhubarb - the poor man's umbrella - lined the crumbling verges. Behind climbed hillsides cloaked in nothofagus, the southern beech trees that trace the Carretera from Balmaceda to the Río Baker. And wherever I looked glaciers hung between snaggletooth peaks that snarled at the sky, as if acting in defiance against the long-departed ice that left such a jagged skyline.

Settlements here are few and far between. Colonisation only really began in the 20^th century and many of the towns are barely 50 years old. There were none of note between Villa Cerro Castillo and the lake to the south, yet still the human footprint had left its mark. In the first few decades of the 20^th century, the government tempted settlers to the untamed wilds of northern Patagonia by offering land titles in exchange for forest clearances.

The fires set for the task burned for nearly a decade in the 1940s, destroying close to three million hectares of forest. While the burning for the most part was carefully controlled, some fires inevitably raged out of control. As we drove on south, the bone-white trunks of fire-scorched trees littered hillsides and valley floors, or rose from the floodplains that flank the Río Baker like ghostly spectres glinting in the sunshine.

Before long we reached the western shore of Lago General Carrera. This, at least, is its name in Chile. The deepest lake in South America and the largest too after Lake Titicaca, General Carrera straddles the border between Chile and Argentina, where it goes by the name of Lago Buenos Aires.

For mile after mile the road snaked beside the lake, whose colours morphed with the changing light of day from gunmetal grey to the striking cyanic blue of lapis lazuli, that inimitably coloured stone mined only here in Chile and in the mountains of Afghanistan. In Puerto Varas, a pretty lakeside town just north of Puerto Montt, I'd seen a number of stores selling beautiful lapis jewellery.

Lapis, however, was not the only stone to surprise me in the region. Close to Puerto Tranquilo is a network of caves made entirely of marble, set in wind-sculpted islands just off the lakeshore. Our boatman, Pedro, weaved us in and out of the marble caverns with nonchalant ease as we gazed at the patterns reflected perfectly in the lake's azure waters. Ask a geologist what turns the water such a clear and unearthly blue and you'll probably hear something about finely ground glacial silt. Instead we asked Pedro. "These waters are magic", was his deadpan reply.

Magic they may be but for how much longer? The same waters feed the great Río Baker, the most powerful river in Chile, a turquoise ribbon that cuts a path south all the way to Tortel, creating chasms, gorges and wild, white rapids. But what's adored by rafters and nature lovers is equally coveted by HydroAysén, a conglomerate of power companies hoping to dam both the Baker and Pascua rivers.

In an effort to bring power to Santiago and the north, where mining operations consume half of Chile's energy, the proposed project would flood national parks and natural reserves, and see high-voltage towers running thousands of kilometres across one of the most pristine parts of the planet. Protestors have so far kept construction at bay, but travellers are tuned in to the looming possibility of environmental damage and are keen to drive the route while the views are unimpeded.

"Visitor numbers are growing all the time", said Stefan, the Dutch owner of eight beautiful lakeside cabins that look out across the water to Laguna San Rafael National Park. The park is home to pumas, dolphins and the 30-metre-high San Rafael Glacier; it's also the location for one of the proposed dams.

But conservation is often hard won. No one knows this better than Doug and Kris Tompkins. Driving up from the Río Baker to their reformed estancia, Valle Chacabuco, we passed herds of guanaco (wild cousins of the llama) surrounded by mountains and sprawling Patagonian steppe. In their former lives, the Tompkins were captains of the retail industry, she as CEO of outdoor clothing line Patagonia, he as founder of The North Face and Esprit.

But since the early 90s they've been busy rehabilitating an over-grazed sheep ranch, removing invasive plant species and more than 644 kilometres of fencing, returning the land to its natural state and securing a safe haven for guanaco, foxes and endangered huemul deer.

The couple were away when we arrived at their lodge, an upmarket affair where guests can stay on a donations-only basis. They'd left instructions for us to make ourselves at home but the twists and turns of the Carretera Austral now had us like a magnet, pulling us trance-like ever further south to our final destination, Tortel.

This unique village, connected by boardwalks hanging over the milky waters of a glacier-fed fjord, was the end of the line for us and for the Río Baker too. Both river and village spill down a steep escarpment to a horseshoe bay, from which boats head out to sea, carrying the cypress wood that supports Tortel's economy. Prince William worked here in October 2000 for Operation Raleigh. Colonists didn't reach here until 1955. Before that it was a haunt of the nomadic seafarers, the Alacalufe.

As I sat on the cypress boardwalk, taking this all in, I was suddenly reminded of a passage from Chatwin: "Patagonia is the farthest place to which man walked from his place of origins. It is therefore a symbol of his restlessness." I too was restless. I missed the sound of gravel crunching under tyres, the smell of dust kicked up by passing lorries, and the sight of vaulting ridges stacked up to the horizon. It was time for the drive home.