The sled moved along silently for hours with nothing but the sparkling black of the night’s sky above them and the sparkling white of the endless snow beneath them. The sled suddenly lurched downward as the topcrust of snow gave way. They were in a hole growing larger every second. Kate brought the engine to maximum, hoping to outrun the collapsing snow, but the hole continued to expand. Soon it was an enormous crater, and they were zooming down the side straight for the center. They continued back up the other side, hoping to escape on momentum, but it got steeper as they went, until they were slipping down a vertical drop. Kate engaged the emergency brakes, and two spikes shot out the bottom of the sled and stuck into the side of the crater, holding it there. Suddenly, everything was still. The avalanche was over. The only sound was the heavy breathing of the shaken people in the sled. “Is everyone alright?” Kate asked when she had regained her breath.