Tinged with grit and dirt it looks like the browned topping of a lemon meringue pie, a million giant-sized white iced gems clawing skywards.
Crammed into a catamaran, we rise to our tiptoes to get a first glimpse of the 65-metre high spikes as they slowly come into view.
“Iceberg, right ahead!” shouts Sophie as we drift to within just a few metres of a jumbo ice cube bobbing gently on the glassy surface. As the light strikes its jagged edges, patches of the frozen water island take on a majestic turquoise hue.
In the distance crampon-clad ice trekkers slowly attempt to make progress in this hostile environment.
They are nothing more than dark specks, barely visible amidst the vast carpet of blankness.
Our boat slows to a crawl and the engine noise is displaced by eerie creaks as the 250 km² glacier flexes in the cool air.
The ship swings round, then right in front of us a huge chunk of ice breaks away from the main body.
It leaves a great cloud of powder in its wake as it plummets into the lake below.
A split second later the delayed eardrum-bursting sound pierces the stillness, with more impact than a gunshot going off in a library.
With little to draw comparison with in this bleak but beautiful scene, it’s difficult to get an accurate grasp of just how close we are to this monolith. But judging by the time it takes for the waves created by the tumbling block to reach us, I estimate it is around 150 metres away.
Their arrival gives our boat a violent shake, indicating that the lump which has just sheered away from the glacier is pretty sizeable.
Although we witness regular ice-falls, the Perito Moreno Glacier in southern Patagonia is actually one of only a handful of glaciers around the world to buck the trend by advancing instead of retreating.
Boasting a bitterly cold winter, it is easy to understand why the sprawling sheet of upward-facing icicles is growing.
Platforms on the bank facing the glacier provide a series of different observation points, including the opportunity to see the enormous blanket from a higher position.
For more than an hour we join the hordes who have flocked to gaze at this tremendous natural spectacle.
Everyone is waiting for the moment, the ‘calving’ where an icy mass crashes into the lemon squash-shaded water beneath.
Patience is the key. When the dramatic ‘freedom leaps’ finally come, they are more than worth the wait.
The energy and power is incredible.
Often one breakaway is followed by others nearby – the sudden change in the iceberg’s composition in one spot seemingly causing shifts and eventual falls in the ice around.
After an hour it’s time to bid goodbye to this breathtaking other world. As we trundle away from the glacier back to the bus, another explosion booms behind us as nature gives us one last reminder of just who’s boss.