How long will Ivory Glacier last?

Geographer David L Harrowfield made his 11th trip to the remote Ivory Glacier in May with a research party, who noted its diminished state.

As the noise of the red Squirrel helicopter faded away, we were left with only the sound of a large waterfall from the lake outflow channel. This flowed down a cliff about 200m high. We stood and briefly gazed in silence at what was left of the Ivory Glacier.

On May 13 a four-member party was flown to the remote Ivory Lake Hut, located at the head of the Waitaha River in South Westland, at an elevation of 1457m. The visit would last four days.

The leader of the party was Warren Chinn, son of the late Dr Trevor Chinn, renowned New Zealand glaciologist. Others were Pete Mason and myself. As technicians we worked with Trevor, Canterbury University staff and students on the Ivory Glacier in the early seventies.

On his first visit was John Rothery. Trevor, Pete and John also surveyed many glaciers during the Hydrology/Glaciology programme in The Dry Valleys of South Victoria Land in Antarctica (1970-75).

The Ivory Glacier was thought to have been named by Trevor, as high on a ridge above is The Tusk, a rugged feature named on early maps. Today the glacier is a mere fragment of what it was when photographed in 1953.

In April 1968 the glacier was again visited on foot by Trevor, Ian Halstead, Eric Saxby and Julian Hawes, during the infamous ‘Wahine Storm’.

Having decided that the location was suitable to study as a Glacial Representative Basin during the International Hydrological Decade (1965-1975), Trevor then ordered a standard New Zealand Forest Service S70 hut.

This was erected in 1970 and glaciology research was then undertaken by the former Ministry of Works Hydrological Survey, in association with the Geography Department of Canterbury University.

In 1972 the hut had an extension added by Trevor and Pete and in 1974 Sugra Morley became the first winter resident, when important meteorological and other observations were made over 196 days. In March 1986 a one-off reunion of all who worked there was held at the hut when 13, including the original builders, attended.

After an inspection in April 2016, the hut was found to be badly in need of repair. In March 2019 it was restored and is now cared for by the Backcountry Trust (BCT).

At the Ivory Glacier, of particular interest was the mass balance of the glacier. That is, the measure of the change in mass of a glacier over one year. Accumulated snowfall contributed to the mass and ablation related to loss by melt and evaporation.

For this recent visit, we had a number of tasks to accomplish during four days at Ivory Lake Hut. Of importance, for future reference and visitor education, was the placement of four information panels in the hut describing the history of glaciological research from 1968 to 1985 and of the personnel involved. Warren produced the panels from historic data and photos collected using his father’s significant and well-organised memoirs and archives.

Warren made his first visit when aged 10 and his second at 12. He said ‘‘all the fuses were blown’’ and he loved the place. Pete and myself, both veterans of numerous early visits, had participated in various science programmes on the glacier together with local scientists and two

Canterbury University geography thesis students (Fergus Harding and Bruce Dickson).

Over the years, many enjoyable leisure moments included skiing on the neve, rowing on the lake, climbing and consuming large pots with soup and stews cooked on a Primus stove. For the latest expedition blue cod and mulled wine was consumed with gusto.

As Warren pointed out, with rapid ablation, the surface slope became steeper and steeper as the recession of the glacier progressed. The glacier then re-established its equilibrium, due entirely to the underlying topography and ice thickness. Now a remnant of its former glory, the Ivory is slowly diminishing in area. How long the glacier will remain is anyone’s guess.

The Ivory is a very special place and the hut has been described by tramping enthusiast, photographer and author Ray Salisbury, in Wilderness magazine, as the ‘Holy Grail for hut baggers’. There is always something of interest here and the hut is a haven for the weary arriving by foot.

Last month, unfortunately, alpine plants had finished flowering and although over the years the local kea population has diminished, a few were seen, including one at the hut. There was the unusual sighting of three resident whio (blue ducks) on Ivory Lake and one evening a weka (a sub-species) was heard calling in the valley below. Cliffs were scanned for rock wrens seen previously, however none were observed, though a New Zealand pipit was seen.

Today all that remains of the glacier, in the back of the basin known as a cirque, is an area of ice and neve behind a steep rock face. There is no longer the terminal face that existed previously or, during summer months, icebergs.

Now there is a very large lake and photographs indicate that about the year 2000, a major loss of ice appears to have occurred, although this was not unexpected.

The four days passed quickly. An enduring memory was a return to this beautiful environment and the many shared experiences.

How long the glacier will remain is anyone’s guess