Charlie has been guiding around Mount Cook on New Zealand’s South Island for long enough to have seen dramatic changes. The Tasman Glacier has retreated “five or six kilometres”, and Tasman Lake has emerged in its stead at the bottom end. It continues to grow, fed by avalanche-diverted streams and rivers, plus ever more ice breaking off the glacier.
It’s not a lake you want to swim in. The temperature is around 3C on even the sunniest of days, but that’s enough above freezing to mean that the more water there is, the more the ice melts. But before it melts, it breaks off. The ice shelf is over 300ft high above the water, but there’s another 900ft below it. When chunks break off, they become icebergs, and the prevailing winds send them down to the bottom of the lake.
Kayaking on the lake would be pretty special anyway. Most of New Zealand’s tallest mountains — including the unmistakable Mount Cook — are in clear sight, while the ‘rock flour’ silt washed down by waterfalls gives the lake an ethereal, magical colour. The icebergs add an extra dimension.
“Remember what happened to the Titanic?” says Charlie. “It ran into an iceberg and it sank. That was made of tons of steel, and your kayak is plastic. So don’t crash into the icebergs.”
Having given this advice, he promptly proceeds to ignore it. The kayaks glide across the lake, and Charlie heads straight for a berg. He attempts to mount the thing, to set it in motion. He’s trying to turn the iceberg over, to show us the clearer, bluer ice underneath. When that doesn’t work, he tries an alternative tactic, pulling an ice pick out of his bag and attacking a protruding chunk on another berg. He throws the ice in a bucket on the back of my kayak, then paddles backwards to admire his handiwork.
Sure enough, the berg slowly lurches and begins to turn. Lop a bit off, and its centre of gravity shifts, causing it to topple. The whiter, sun-aged parts crash into the water and sections of the clearer 90% below the surface rise up. Being in a kayak allows for closer inspection, so we pull over alongside one of the bigger icebergs. It is, according to Charlie, not a patch on what can sometimes be seen here. They can, apparently, get as big as 10-storey buildings, rising 150ft in the air.
This one’s barely a tenth of that, but it still feels like a relative giant on the water. On inspection, there are large chunks of rock inside it, presumably collected by the glacier over time. “This ice is up to 10,000 years old,” says Charlie. “And once it has broken off, it might last a couple of weeks before melting.”
After paddling back to shore, Charlie takes the bucket of ice and pours out a slab-like outcrop. He picks up a rock and says: “It’s ancient ice, so let’s break it the ancient way,” before smashing it up with a nearby rock. He hands out plastic cups, plonks a chunk of ice into each and pulls out a bottle of whisky.
“Why have Scotch on the rocks, when you can have Scotch on the bergs?” he says, pouring the Grants over the chunks of glacier that are about to meet an extremely agreeable end.