Wednesday 17 March 2021 Hilde Fålun Strøm didn’t realise it was a polar bear at first. Reaching the crest of the ridge on her snowmobile, she could make out Bamsebu, the remote trapper’s cabin where she and her expedition partner, Sunniva Sorby, were spending the long, dark months of the Arctic winter. But as she peered through the blackness of the February afternoon, the familiar shape of the hut appeared to be hidden behind what looked like a large snowdrift. For the first time, the pair had decided to leave their dog, a two-year-old Alaskan Malamute called Ettra, behind when heading out to explore. They had also left their hand auger - the heavy manual drill they used to take samples of the ice – in its bright red box outside the front door. But as Strøm swung the snowmobile round, catching the cabin in the beam of its powerful spotlights, neither she nor Sorby, riding pillion, remembered that.