Access

Tasman Glacier is signposted 7km along Tasman Valley Road, 1 km from the settlement of Aoraki/Mount Cook. There’s a large, but sometimes not large enough, parking area with toilets.

Track

From the carpark, the metalled track climbs over 70 metres to the top of the terminal moraines above the lake.

Two side tracks are possible on this walk:
The Tasman Glacier Lake (1 hour return 2.6 km), which branches off shortly after the start of the walk on the right.
And a short detour to Blue Lake (5 minutes return).

Blue Lake is also visible from above as you climb the steps to the lake viewing area. Floating icebergs stud the grey waters of the lake and in the distance the ice cliffs of the glacier’s terminal face occasionally calve. Rock debris covers the glacier, so it is difficult to make out the white of the ice flow.

On the opposite side of the valley are peaks such as Mount Blackburn, The Nuns Veil and The Acolyte. Mount Tasman is concealed in the far distance.

Geology

Previous to glacial action, many valleys were characterised by a system of interlocking spurs protruding into the valley floor – the legacy of water’s erosion carving V’s into the land. Glaciers worked differently and having no regard for these obstructions, simply bulldozed through the rock, truncating spurs to leave a triangular face bisecting the former ridgeline.

Glaciers filled the valleys and joined in the upland areas to form ice caps. The last Ice Age was known as the Otiran and occurred between 80,000 and 10,000 years ago. Ice was up to 2 km deep. Sea levels were up to 120 metres lower and ice reached over 10 km off today’s shoreline. At least 5 glacial advances and retreats are evident. At the conclusion of the last glacial between 35,000 and 14,000 years ago, a Glacial Maximum occurred, a short but intense episode of global cooling. This spurred on the glaciers in a final pulsing advance, which built up the vast terminal moraines, filling the McKenzie basin and extending glaciers 10 km past the current southern shores of Lake Pukaki. These details give some fuel for thought on the rapidity of climate change that occurs without the influence of humankind.

The Tasman Glacier is New Zealand’s longest. A series of Photoshopped photos on a revolving sign at the lookout show the glacier’s height in recent times. And it’s staggering rate of retreat. Currently the glacier is 23.5 km long, covers 101 square kms and is around 600m thick at it’s maximum depth. The terminus is 200m deep.