Vatnajökull

Skaftafell is a green wedge of birch and heath held between two tongues of ice, and it is the easiest place to stand inside the ice’s work without touching the ice itself. For a long time it was a farm; later a national park in its own name; now it is one corner of the reserve wrapped around the country’s great glacier. From the base, the valleys open on either side in the same broad, round-bottomed shape — the signature of a river of ice rather than a river of water, which grinds a valley flat-floored and steep-walled instead of cutting a narrow V. Trails climb from here toward the falls and the ridges, so the place works as a doorway more than a destination. Take a moment before you walk up. The flat gravel spread out in front of the green is washed-out debris, sorted and dumped by meltwater and by the floods that burst from under the ice — the raw material of everything the glacier leaves behind once it has finished carving.

Kristínartindar is the high seat above Skaftafell, a summit whose knife-thin crest straddles two glacier valleys at once, one falling away on each side. Standing on that edge is the clearest lesson the ice teaches here: the ridge is thin because two separate bodies of ice ground down toward each other for a very long time, each shaving its own valley until only a blade of rock was left between them. On a clear day the view reaches the country’s tallest waterfall, dropping off a cliff the ice uncovered as it shrank back. The way up is long and steep — a full day’s loop climbing more than a kilometre from the valley floor — and the trail opens only in the warm months, once the snow has cleared. Save it for good weather and an early start. The summit gives nothing in cloud, and the country it lays out is the whole reason to climb.

Stuðlaberg is a reading stop on the walk up toward the falls, and its name is the local word for the very thing it explains: columns of old lava, stacked close like a bundle of dark pencils. The rock here began as a thick sheet of molten basalt that cooled slowly and evenly. As it hardened it shrank, and shrinking rock cracks — the fractures started from many centres at once, met in a honeycomb, and drove straight down, splitting the whole sheet into six-sided posts. The ice and its meltwater did the rest, stripping the soil and softer rock off the top and standing the columns bare for you to see. Pause at the board, then look past it to the exposed rock in the gorge walls around you. The same pattern repeats wherever the old lava has been laid open, which here is nearly everywhere the ice has scoured down to bone.

Svartifoss is where the columns and the water meet. A stream off the high ground drops over a lip of dark lava, and behind the falling water the cliff is ranked with the same six-sided posts of old basalt, curving inward like the inside of a shell. The falls sit at the head of a gorge the ice and meltwater have opened, and the show is not only the water. Look at the ground at the base: it is littered with sharp broken columns. Here the rock is losing its lower supports and snapping off in fresh sections faster than the water can round their edges, so the wall stays angular — freshly quarried rather than worn smooth. It is a rare place to watch a cliff take itself apart on a human timescale.

Jökulsárlón is the ice’s other lesson: not what it carves, but what it leaves when it withdraws. A lifetime or two ago there was no lake here at all — solid ice reached down toward the sea. Then the glacier began to pull back, and the hollow it had gouged below sea level filled with meltwater. The lake has grown several times over within living memory, and it now ranks among the deepest in the country, floating slabs of ice that break from the retreating front and drift toward the ocean. The water is the plainest clock for the ice you will find: every stretch of open lake is ground the glacier has given up. Stand at the outlet where the ice crowds toward the sea and watch a slab go grey, then clear, then gone. The front is a few miles back from the water now, and the gap widens with the warm seasons. It is a quiet place to feel how fast a glacier can retreat once it starts.