"It's worth bringing a head torch," I was told, "and a hat to sleep in, especially if you feel the cold." As I approached my shelter for the night – a dome of snow rising like a blancmange on a large white plate – this ominous warning came back to haunt me. Sleeping in an igloo had seemed such a good idea at the time: a way of pushing the boundaries, doing something more challenging than just skiing. But as I inched nervously towards my new home, then crouched on my hands and knees at its tiny entrance, the notion seemed more than a little foolish.
Apart from a team of huskies, there were only three of us there in the icy wilderness – my sister, myself and our guide, Philippe – encircled by the jagged, powerful peaks of the Champsaur valley. It seemed an unlikely spot for an igloo, this undiscovered pocket of the southern French Alps, 2,400m up on the Rocherousse plateau. My sister and I braced ourselves, before burrowing deeper inside.
The igloo's interior is chiselled out from solid snow. Not only did we get stuck crawling through the narrow shaft, but the snug main space at the end wasn't tall enough to stand up in. The only furnishing was a plastic mattress that lay uninvitingly at our feet.
A bookshelf fashioned from snow appeared to be a preposterously optimistic design feature. The igloo usually sleeps four, but as we were the only visitors that night, we'd agreed that Philippe should stay there as well: his cooking skills would come in handy, as would his outdoor expertise. Despite his confidence and competence, though, log fires and downy duvets held a dreamy appeal.
Back outside, the solitude up there, lonely in the Alps, was intense. The sun, a burst of orange, flared one last time before slipping behind the mountain, casting an eerie crimson glow across the snow.
Suddenly, a chill swept over us: Philippe suggested a snow-shoe walk to keep us warm. With the requisite winter footwear strapped to our feet, we skimmed the surface of the thick powder. There was no noise pollution, no light pollution.
"Listen," whispered Philippe, holding a hand behind his ear. We were a good kilometre away from the huskies now, but their sensitive hearing had picked up Philippe's voice. They yapped agitatedly in response.
"You're not cold, are you?" Philippe asked once we were back in the igloo, sitting cross-legged on the mattress. It was –5C outside, and only a couple of degrees warmer inside, but Philippe was still without gloves. Despite layers of padding, my own fingers and toes had turned numb. When Philippe popped a pan of water on a burner to make caramel tea, I sought warmth from the flame, watching as he continued to bring provisions out of a bag: two baguettes frozen solid, a box of fondue mix, and a smorgasbord of local salamis.
Philippe lit a couple of candles, promising that they would help warm the igloo to a scorching 5C. Within minutes, my extremities had thawed, and soon we were twirling squares of now-defrosted bread in a cheese fondue before hungrily downing cold cuts and pre-packed crêpes.
Later, stepping out for some night air, the inky sky was a breathtaking dazzle of diamante. It was now a chilling –20C and it was a relief to return to the relative warmth of the igloo. We unrolled sleeping bags, pulled on hats and wriggled inside. "Bonne nuit," said Philippe, closing the igloo with an ice-block before blowing out the candles.
The next morning, the roof of our igloo twinkled like an ice sculpture, close enough to touch. Breakfast was a leisurely affair, snuggled in duvets, dunking cold brioches in hot drinks. Eventually we exited our cocoons, braving the cold to locate the skis and boots we'd brought with us. This is the real pay-off when staying in an igloo: we'd been the last people up the mountain, and now we intended to be the first ones down – owning the slopes while the rest of the Alps slept.
We spent the remaining nights of our trip in a basic chalet on the fringes of Orcières 1850. Here there was more than enough to satisfy advanced skiers for a few days. There was also husky sledging on offer. We tried it out and were surprised by the rush, as we held on to our reins for dear life while the dogs raced through thick powder.
On the slopes, €12 bought a serving of tartiflette (creamy potatoes with cheese and bacon) and also dessert and coffee. Off the slopes, Le Cro Magnon, a tucked-away tavern, served the most mouth-watering duck stuffed with goats' cheese and honey. Nothing, though, quite matched our fondue, eaten on laps in an igloo. Did we shiver? Yes. Was it comfortable? No. But the achievement made this a ski trip to remember.
Traveller's guide: A night in an igloo
Undiscovered Alps (0845 009 8501 or 00 33 677 36 2942; undiscoveredalps.com) offers a winter multi-activity holiday from €584 per adult. Price includes seven nights' accommodation, a six-day ski pass, equipment and activities including a night in an igloo.
Orcières 1850 tourist office (00 33 493 55 8989; orcieres.labellemontagne.com)