A personal account of a hiking trip to Los Glaciares National Park in Patagonia, visiting El Chalten, Piedra del Fraile, Marconi Glacier, Paso Marconi, Southern Patagonian Ice Cap, Circos de los Altares, Cerro Torre, Torre Egger, Cerro Standhardt, Paso del Viento, Lago Toro.

It's 4am. I put on all my clothes and go outside to help dig our tent out of what is rapidly becoming a snow grave. I ignore the mountains soaring above me - because this is the second time I have been up tonight and because it is extremely cold and very, very windy. This is Patagonia, after all, and we're camping on an ice cap.

The Southern Patagonian Ice Cap is a great ocean of ice that sweeps west from the coast of Chile to the border of Argentina. It is one of the largest expanses of frozen water to be found outside the polar regions, nearly 350km long and at times 90km wide. Home to some of the most extreme weather conditions in the world, the smooth surface of the ice cap allows storms generated deep in the Pacific Ocean to race unimpeded and gather momentum before slamming into the Southern Patagonian Andes with a force generally uncommon in the northern hemisphere: apocalyptic.

Nearly 170km of these Southern Patagonian Andes have been designated as the Los Glaciares National Park, a collection of heavily glaciated, sheer-sided peaks that rise steeply out of the vast semi-arid plains that cover the landscape. Two of the most spectacular mountains in the world, Mount Fitzroy and Cerro Torre, are in this park.

New frontier

Access to these mountains is via El Chalten, a dusty frontier-type village nestling in a small horseshoe valley at the head of the nation al park. El Chalten is 220km from its nearest neighbour, El Calafate, which is itself a three hour plane journey from Buenos Aires. By any standards, the location is remote.

Mount Fitz Roy dominates the area, by virtue of its sheer size and bulk. Standing 3,441m high, it soars above the village and its neighbouring peaks, spouting out rivers of ice and satellite crests that overshadow everything except the Torre Range, a collection of needle-like spires 7km south. Undisputed queen of the Torres is Cerro Torre, the Tower Mountain. It rises vertically for 3,128m and is generally regarded as one of the most difficult in the world to climb. That's not because of the altitude or highly technical climbing, but by virtue of its location: standing sentry for the Southern Patagonian Ice Cap. Cerro Torre lies right on its edge. Once described by the South Tyrolean climber Reinhold Messner as "a shriek turned to stone", the mountain receives the full brunt of the prevailing weather. The freezing conditions, coupled with the almost constant high winds, regularly see Torre and its adjacent peaks covered in a maelstrom of moisture-laden, boiling storm clouds and coated in a rime of perilous, and at times unclimbable, snow and ice mushrooms.

Cerro Torre presents its west face directly to the Southern Patagonian Ice Cap. It is home to one of the most difficult climbing routes on the mountain: 2,000m of vertical - and at times overhanging - rock, snow and ice. Its main defence, apart from the difficulty of climbing and the atrocious weather, is remoteness. It can be reached only by those few who manage the ice cap itself and, weather permitting, zig-zag their way south for 25km around a myriad of crevasses to the Circos de los Altares - Corrie of the Altars.

International: no rescue

Circos de los Altares is a deep glacial scoop, rough-hewn from the west side of the Torre range by many years of glacier excavation. Enclosed on all sides except its front by sheer granite peaks and with its mouth facing the ice cap, it is a spectacularly beautiful and at the same time threatening place - there is no mountain rescue here if things go wrong.

Which is what appears to be happening as, with us committed to the ice cap, and camped deep in the corrie, the weather takes a turn for the worse and we are forced to repeatedly get up in the night and dig our tent out of the snow drifts that threaten to bury us in the ground and result in us being tent-bound for three days.

When we're finally allowed to leave the corrie, it takes us nearly all day to travel the 20km south to the nearest exit to the ice cap, Paso del Viento - Pass of the Winds. It is a strangely quiet place, given its name and the preceding days' conditions.

Despite the weather, we reluctantly turn our backs on the ice cap and head off on the two-day trip it takes to descend the glacier, traverse endless moraine, and climb up and down steep-sided valleys to return to El Chalten.

In El Chalten I spent two days in March recovering from the nine-day, 120km round trip to Circos de los Altares. I had followed in the footsteps of Gregory Crouch, an American author and climber who entered the ice cap during the Patagonian winter of 1999 with a party of companions, set up a base in the corrie, and climbed the west face of Cerro Torre. Like his book said, the views didn't disappoint.

Visit Patagonia

I've written a Patagonia travel and trekking guidebook which includes all the details for visiting Los Glaciares National Park.