By way of contrast, the last volcanic eruption in West Iceland occurred almost six centuries ago near Hallmundarhraun. It was a huge event, resulting in the longest lava cave in Iceland, Viðgelmir (148,000 cubic metres – more than three and a half cubic miles).

Unlike Chile, which has ski lifts on or near the lower slopes of five volcanoes, the skiing on Iceland’s volcanoes can only be reached on foot – or by helicopter or snowcat.

There are 11 ski areas – mainly clustered around Akureyri. In terms of terrain, Hlíðarfjall – just under four miles from the town – is the largest, with almost 10 miles of slopes, and a vertical drop of 1555 feet. The Akureyri region has six ski areas all told, and five of them are available on one “5X5” pass. They tend to be on the small side, but Hlíðarfjall in particular will keep most skiers happy for a day or so.

“The skiing on Iceland’s volcanoes can only be reached on foot – or by helicopter or snowcat.”

After skiing Mt. Hlíðarfjall’s five lifts, we moved on to Sauðárkrókur, which in spite of only having one lift has some good off-piste and a long back-country route back down to the main road. Next came Siglufjörður, with four lifts serving almost three and a half miles of runs (1475 vertical feet), and finally Dalvík Ski Area at Mt. Böggvisstaðarfjall – two lifts serving more than three miles of slopes, with a vertical drop of just over 900 feet. We didn’t ski the fifth of the “5X5” resorts, Ólafsfjörður on Mt. Tindaöxl as the ski area was busy hosting ski races. But in any case, with only one lift and less than a mile of skiing it’s the smallest of the five ski areas covered by the 5X5 pass.

And finally we’re off. Unusually, the seat cushion backs have been removed to make space for our airbag packs, so that we don’t have to remove them from our backs. They have built-in avalanche airbags which instantly inflate two “balloons” if you pull an electronically powered toggle in the event of an avalanche. (Don’t forget to switch them off in the helicopter – and back on again at the top of each run!)

These airbags are designed to keep skiers on the surface in the event of an avalanche and help prevent them being buried. We also have radio telephones in our packs which in theory we don’t need to use except in an emergency. The volume is turned up high so that routine instructions from the guide can be heard without needing to remove them.

In the Alps or Rockies it can sometimes be hard to take in the more distant peaks because those in the foreground dominate the skyline. But in Iceland you can often see myriad mountain-tops receding into distant seascapes.

Although the peaks are not as high as their Canadian counterparts, the fact that many mountains start off literally at sea level makes them look just as dramatic and utterly awe-inspiring. Almost hypnotic in fact, often lined with multiple narrow streaks of dark rock that shows through the snow, which make you stop and stare at them across the steep-sided valleys before taking yet another plunge down the mountain.

The quality and length of the runs we ski is deeply impressive and unexpected – just as good as anything I’ve experienced in the global heli-ski capital Canada. In good snow, with our wide-bodied skis, and helped along by the relatively low altitude, we can plunge almost effortlessly for a hundred turns before thighs start to burn. We even manage a “first descent” of 2,500 vertical feet – Iceland by definition is full of runs that have never been skied – and we decide, since there are three Brits in the group, to name it Union Jack.

The rest of the group seem to be impressed with my efforts, calling me the “David Attenborough” of skiing. Since the great man is now 90, I wasn’t sure how to take this. “We mean your encyclopaedic knowledge about skiing,” they added hastily.

But even our relaxed and exhilarating descents were finally challenged late in the day on a run called South Peak when dropping temperatures suddenly made our turns more difficult. “Finally we’ve found Mr Crust,” grinned JB. We called it a day. But what a day!