Timing

This is a fair weather track, as Glacier Burn can rise quickly and be difficult to cross on the return journey.

Access

The parking area is signposted 5 km from end of tarseal on Greenstone Road.

Track

Follow the orange topped posts over the stopbank and cross Glacier Burn. This may be tricky after periods of rain.

The track enters the towering beech forest and climbs progressively. Crown ferns and mossy patches carpet the forest floor. Approaching the treeline views of the impressive basin appear above.

Beyond here it is a mountain area and if you venture further you should be aware that there is plenty of rock that could fall on your head.

And be sure to know how to find the orange triangle to get back on track.

Geology

Over the last 2 million years the Earth has undergone at least 12 glacial episodes, times when the global climate is significantly cooler than today. The rain falls as snow in upland areas, compacts, and over time forms vast ice sheets.

Geologists have purported various theories for why Ice Ages occur. Today it is generally accepted that since Antarctica has occupied its present position, and allowed a large ice sheet to develop over the land’s surface, this has had the effect of reflecting large quantities of solar radiation back to space (white being the best reflective colour). Once coupled with the fact that solar output of radiation is not a constant (it varies on a 40,000 year cycle) and that the orbit of the Earth around the sun is not a perfect ellipse (the wobble is on a periodicity of around 100,000 years), the changes in the global solar radiation budget can vary enough for episodes of global cooling to occur.

During the last glacial episode, ice stacked up in the upland areas of the Southern Alps and weaved ways down the valley courses to either side. Whereas water leaves a V-shape in a valley profile, the glacial signature marks a characteristic U-shape. The glacial bulldozers charged through whatever lay in their paths and the U-shaped valleys, already carved by previous glaciations, were deepened and their form accentuated. The Hooker Valley are apt examples of this distinctive profile.

As the weight of ice scours down the headwall of a watershed, it nibbles back at the head of a valley until it meets the glacier of the adjacent watershed. The bowl at the head of a valley is a cirque, well illustrated at Glacier Burn.

Hanging valleys are the remains of a tributary glacier that met the main valley glacier. Smaller glaciers harness less erosive power and are less able to incise deeply into the bedrock. They thus meet the main valley glacier at the same height, but do not cut down as deep. When the glaciers melt, the hanging valleys are left perching above the main valley.