The other side of life in the wild: a Sami hut and drying reindeer hide near the Sitojaure lake.
Between me and the next stage of my hike is the Sitojaure lake. What to do? I try my Moses trick, but the force is not with me. I consult the map. Further downstream a hut is marked and I am hopeful it is a Sami settlement. The only people allowed to leave anything more permanent in the Sarek than a footprint are the Sami, who as the aboriginal inhabitants, have ancient reindeer herding rights here. I have heard that Sami boatmen are sometimes happy to take hikers across lakes.

There are no koti, just a few small wooden cabins. I make enquiries. A young woman tells me that the men are away marking the reindeer calves, but she could take me across, or I could row myself - only 3km! It's the first option, of course, and I am amazed at how she navigates a tortuous crossing, avoiding rocks and shallows, and using what drift there is. How was I supposed to have managed that? We make it across in about 25 minutes, and I hoick up my load to press on up the mountain. The koti are on this side of the lake, and there are reindeer hide hanging out to dry, but no sign of the men.

I have a steady climb to the top, but cloud is thickening and when I arrive there is very little view as the fog has descended. The wind picks up and I heed the warning and re-clothe myself - just in time for the rain. Visibility is reducing rapidly, and I am wary of my footing as my route is due to take me across the top of Skierffe, a flat-topped peak with a sudden 679m precipice. I had hoped for a good view of this - even a cautious peak over the edge, though I have no head for heights - but it is not to be. The rain is tipping down steadily, and in spite of all my precautions, I am getting wet, cold and feeling utterly miserable. My fingers are so numb I cannot adjust my rucksack. I lose all sense of how far I've come. This is the other side of life in the wild.

According to my map, if I can remember, as my hands are too numb to retrieve it from my pocket - there should be a large rock en route, which has a holy significance for the Sami people. I peer into the fog for this rock, hoping for shelter and some respite for my hands, but it seems hours before it appears. When it does, I understand its magical qualities. It is split by three crevasses, all of which join in a central spot, into which I crawl for some rain-free moments. As the blood returns to my fingers I remember the Kendal mint cake I was given by my colleagues as a parting present. It seems the right moment to have some comfort food, and I nibble away, remember Hillary and Everest and feel less sorry for myself.

There is no let up in the rain or wind, so I have to push on. This slow progress will already have caused delays in my (very rough) plans. A small mountain cabin is marked on the map not too many kilometres away (I guess), and I keep that image in my head as I plunge into the fog again. It is a slow, wet process, but eventually I am descending through the trees and over slippery boulders to that wooden haven. There's a wood stove and some logs, and soon I have a cosy fire going, a cup of tea on the boil, and the world looks brighter. A couple of hours later a rattling door announces the arrival of five more dripping hikers, sodden down to the last raisin in their rucksacks. We decorate the stove with socks, T-shirts and fleeces, and stand back to admire the Chinese-laundry effect, then settle down for a snug night.

All is forgiven when the next day dawns, blue and still. I give up on peering over Skierffe and head for Nammasj instead. It stands like a sentinel in the Rapa Valley with the delta of the Rapaadno River swirling below. This river is fed by the huge glacier at the head of the valley, and unlike the other lakes in the area, it is a milky colour. The Sami don't like to fish here: the fish cannot see the bait! The ascent is easier than it looked, and I am rewarded by stunning view of the Rapa Valley - the main artery of the Sarek. I have a willow warbler for company, but all else is still. The pace slows to match the ancient feel of these mountains, and the river is just a bass-clef murmur below. I warm against the rocks and feel the sun on my face, content to be one with all this grandeur.

• Chelsia Tongue is Guardian Unlimited's grey Netjetter, having won a competition to take her dream trip to the world's hot and cold wildernesses. You can email her support and suggestions at chelsia.netjetter@theguardian.com and read her competition entry here