Deep inside Hochkogel mountain, have guide Siggi Kahl is getting ready for his tour. Using a flaming taper, he lights bid-fashioned carbide lamps, and hands them one-by-one to his guests. ‘These are the only lights allowed in the cave, so please, no torches or mobile phones. Also, I hope you’ve all brought a warm coat!’ He takes a headcount then heaves open a cast-iron door bolted into the rock and steps into inky blackness.
Inside, the reason for Siggi’s warning becomes obvious. Within a few steps of the cave’s entrance, the temperature plummets to within a sliver of freezing. Breath steams and fingers chill. Up ahead, a staircase disappears into the gloom, and high above, a line of lights from another group bobs and sways like fireflies in the darkness. ‘Now I am afraid we must do some climbing,’ Siggi says, rubbing his hands together for warmth. After a few minutes, Siggi stops and takes a strip of magnesium from his pocket.
Touching it to his lamp, it catches light with an electric-blue flash, sending shadows dancing onto the walls. ‘This is where you see why we call this Eisriesenwelt,’ Siggi says, holding the sparking magnesium aloft. ‘Welcome to the World of the Ice Giants.’ From the gloom, a great column of blue-white ice materialises beside the staircase, its surface gleaming and glinting like crystal in the lamp-light, and its upper reaches lost in the darkness. From inside, there’s the faint sound of water trickling as the ice melts – the same process that’s carved out the cave over millions of years. ‘This is the largest ice formation we have here,’ Siggi says, lighting another magnesium strip as the first sputters and dies. ‘And it’s still growing. It’s added more than a metre this season.’
Eisriesenwelt — above the town of Werfen – is one of many ice-caves in this part of the Austrian Alps. They’re caused by a geological peculiarity; their chimney-like shape draws in cold air in winter but prevents the ingress of warm air in summer, meaning the water inside freezes but never fully thaws. Gradually, the ice builds up inch by inch, foot by foot, and over millennia accumulates into huge formations. Though many of its structures are ancient, the ice itself is dynamic, changing with every passing year. Pillars grow and dwindle. Tunnels appear and vanish.
Stalagmites and stalactites intertwine before melting into nothingness. ‘The cave is closed for winter as it’s too cold inside,’ Siggi says, as he passes a huge serac of ice, like a wave frozen in motion. ‘When we reopen in spring, it’s amazing how much has changed. Often we have to move the path because the ice has altered shape or moved. It’s almost like it’s alive.’ For Siggi, the Salzburgerland is an area where it’s impossible not to be awed by nature’s power. ‘The cave guides here have a joke,’ he says, catching a few rays of sunshine between tours. ‘We have the best office in the world, but the central heating needs some work.’ He grins and picks up his carbide lamp, stuffing extra rolls of magnesium into his pockets, then heads back into the icy underworld.