If an avalanche occurs in the mountains and there is no one to hear it, does it make a sound?

Yes it does. And that sound can be used to count, measure and map avalanches. Leighton Watson from the University of Oregon in the USA, with colleagues, has tested a system of using microphone arrays to detect and characterise avalanches falling on to the Milford Road. They installed two sets of “infrasound” sensors near the Homer Tunnel in September 2020. The very next day the Waka Kotahi’s Milford Road Alliance triggered seven large avalanches in the area by dropping explosives from helicopters onto the mountain snow pack. Leighton’s microphones clearly recorded the sound of the avalanches. In fact the sounds were stronger than had been recorded anywhere else in the world. Through cunning trigonometry of the arrival time of the sound at the different microphones, Leighton was able to track and map where the avalanches were occurring. His maps were validated by the observations of the Milford Road Alliance avalanche team. The microphones were left in place for a month and continued to collect avalanche sound data, including naturally occurring night time avalanches. In each case the avalanche location was mapped. Current avalanche risk assessment relies on incomplete avalanche occurrence data, as observation techniques rely on human observation of events or debris. This is problematic in remote regions or during low visibility in storms or at night. Leighton and his colleagues have demonstrated a new approach which could improve avalanche frequency knowledge and make our mountains safer.

Watson, L.M., Carpenter, B., Thompson, K., Johnson, J.B., 2021. Using local infrasound arrays to detect plunging snow avalanches along the Milford Road, New Zealand (Aotearoa). Nat Hazards. https://doi.org/10.1007/s11069-021-05086-w

A last view of the North Island glaciers

Possibly the most viewed glaciers in New Zealand are those on Mt Ruapehu. Everybody who drives, flies or takes a train past this largest of the North Island volcanoes cannot help but have their eye drawn to its ice clad summits. Its quite likely that many of us are unaware that what we are seeing are the last remnants of great ice bodies that have persisted for 50 thousand years.

To help explain the special case of Mt Ruapehu glaciers, Shaun Eaves and Martin Brook have published a comprehensive review of glaciers and glaciation of the North Island in the New Zealand Journal of Geology and Geophysics.

Fourteen glaciers grace the slopes of Mt Ruapehu and represent the last of the North Islands glaciation. In the past glaciers provided extensive cover over Mts Ruapehu and Tongariro, were probably on the slopes of Taranaki and some remote basins in the Tararua Ranges and perhaps on the tops of the Kaimanawa Ranges and a niche or two in the Ruahine Ranges.

The review highlights the unique volcanic location of the Ruapehu glaciers. The glacier’s inter-twining, sometimes literally, with the area’s volcanism provides valuable age markers to assist with glacier extent aging. No other glacierised region of New Zealand has this feature.

For all the great glacier-volcanic interaction, the review has come too late for the Whakapapa Glacier. The review describes how in the 1950s the glacier flowed 1.5 km from the edge of the mountain’s summit plateau down to the slopes of New Zealand’s largest ski field. Since then it has retreated, split into two and is now nothing but a snow patch that, in some summers, leaves nothing to see.

The demise of the Whakapapa glacier appears to be the first of many as the theme of retreat and thinning is common to nearly all the mountain’s glaciers. The review suggests that next few decades are predicted to be the last for most of the remaining 14 North Island glaciers.

It might be wise to take an extra look at the white capped mountain this summer when you next drive/fly/train past. It just may be your last chance before the end of the glacial life of the North Island.

We’ve lost 216 glaciers!

Sabine Baumann from the Technical University of Munich has just finished counting New Zealand’s glaciers and found that we are missing 216 of them. Sabine carefully counted every independent area of ice larger than 1 hectare, even those bits of ice hidden under rock.

In total 2918 glaciers were found, but in 1978 there had been 3134. It seems that 216 glaciers have melted away.

The total area of glacier has shrunk by 364 km2 , that is a about the size of Manakau Harbour.

Just 15 of the glaciers were in the North Island (all on Mt Ruapehu), three less than the 1978 count.

The new glacier inventory has been published in the Journal of Glaciology

The 1978 effort was undertaken by Trevor Chinn and was published in 2001 in the Journal of Hydrology (NZ).

2021 SIRG Meeting dates

Keep the 9th to 13th February free in your calendars.

For 2021 the New Zealand Snow and Ice Research Group will join with Antarctica New Zealand for a combined meeting in Christchurch at the University of Canterbury.

The current plan is to have the snow and ice themed presentations on Thursday the 11th and Friday the 12th of February.

There will also be a one day field trip at the end (Sat 13th) for those keen to explore glacier-climate in the Canterbury high-country.

The official meeting web page is being hosted by Antarctica NZ with a link to it from the SIRG web page

So keep those dates secured in your diaries, updates coming soon!

Listen to millennial-scale glaciation

Hamish Prince, a post-graduate student in the School of Geography at the University of Otago, has put together a musical interpretation of the ‘Millennial-scale pulsebeat of glaciation in the Southern Alps of New Zealand’ (Strand et al., 2019).

This lets you listen to the (asynchronous) relationship between cold periods in the Northern and Southern hemisphere over the last 50,000 years.

In a review of Strand et al., 2019, it was suggested that if North Atlantic cold periods were a jazz rhythm, New Zealand’s glaciers accent the back beat. To explore the potential ‘anti-phased timing’ Hamish created a drum beat using the timing of both events, ordered from oldest to most recent. The timing of Northern Hemisphere cold periods were standardized and used to define the bars in the music. The position of New Zealand glacier advances were then placed in the music relative to these. A four bar rhythm appeared from the data and from this Hamish wrote a short composition. This lets you listen to the (asynchronous) relationship between cold periods in the Northern and Southern hemisphere from the last 50,000 years.

Such link in the rhythm of the North Atlantic cold periods and the Lake Pukaki moraine dates suggest some sort of a connection between New Zealand and Northern Hemisphere glacial fluctuations over the last 50,000 years.

New Zealand glaciers play reggae.

If the jazz rhythm of cold climate is defined by North Atlantic iceberg activity, then New Zealand’s glaciers accent the back beat.
That is the finding of Peter Strand and collaborators as described in their recent paper in Quaternary Science Reviews.
The signature beat of Northern Hemisphere cold periods during the last glacial period (since about 90,000 years ago) are known as Heinrich events.
Hartmut Heinrich found layering of rock sediment on the bed of the Atlantic that wasn’t local. It had arrived by iceberg transport. Dating when each of these layers of foreign rocks were deposited provided a good indication of when the Northern Hemisphere was cold. Other efforts to date Northern Hemisphere cold periods aligned well to Heinrich’s rock layer dates, so his name has been associated with these cold Northern Hemisphere events.

When considering the current rapid change in global temperatures, it is not unreasonable to look to the past to see how temperature changes were manifest.
One point of interest is whether there is synchronisation of Northern and Southern Hemisphere temperatures.
The lines of rock on the hillsides above New Zealand’s Lake Pukaki represent past extents of a former glacier. Peter Strand and his colleagues found that each rock-line was deposited by the glacier at different times during the last glacial period.
If the Northern and Southern hemisphere temperatures were synchronised, then the dates of these moraines should align with the Heinrich events.
They don’t.
The dates of these moraines fall between the Heinrich events. It seems that when the Northern Hemisphere was cold, The Pukaki glacier was in retreat, and when the Northern Hemisphere was warm, the Pukaki glacier advanced to build these moraines.


Trevor Chinn 1938 – 2018

It is with great sadness that the New Zealand branch of the International Glaciological Society and the wider snow and ice research community acknowledge the passing of Dr Trevor Chinn.
Trevor died yesterday morning (20th December 2018) following a recent stroke.

Trevor was an integral part of snow and ice research in New Zealand for over 50 years. His knowledge of the New Zealand and Antarctica cryosphere was immense, he had an impressive publication record, and undoubtedly, the best known knowledge of glaciers large and small across the entire Southern Alps. His passion for the mountains, and drive to better understand snow and ice processes, meant that Trevor spent many hours in the field. He was a key player in the initiation of New Zealand’s first glacier mass balance programmes on Tasman and Ivory Glaciers, and later pioneered the end-of-summer snowline monitoring programme, which has evolved to one of the most comprehensive glacier data sets in the Southern Hemisphere. Trevor had an energy and spark that was contagious. He loved to engage with students and delighted in encouraging the next generation of scientists – especially with a cheeky challenge to their hypothesis or interpretation.

Trevor’s outgoing personality meant that he was not only good at doing science but great at communicating science. He was the go-to person for media and education. His ability to take complex scientific processes and explain them to a general audience was legendary, especially the way his animated explanations were often accompanied by one of his original glacier-cartoons!

Trevor was awarded a Doctor of Science from the University of Canterbury in 2007, having completed a Masters in Geology there back in 1975.

In 2016, in recognition of his outstanding service and contribution to glaciological research in New Zealand and Antarctica, the International Glaciological Society awarded Trevor with the prestigious Richardson Medal.

Our hearts and thoughts go out to Trevor’s family and friends, and to all those whom this ‘glaciologist- extraordinaire’ touched during his amazing life.

A memorial service is being planned to celebrate Trevor’s life in the New Year. We will provide details of this nearer the time.

2017 Highlights

To follow is a copy of the email sent out on the SIRG email list by Heather Purdie, the New Zealand correspondent to the International Glaciolocal Society.

Kia ora SIRG,

Another year has almost passed so here is a quick run-down on some of the 2017 SIRG highlights…

 2017 kicked off with the’ International Symposium on the Cryosphere in a Changing Climate’ hosted at VUW in Wellington. Thanks to all SIRG members who helped to make this an exciting and successful symposium. Check out the latest issue of ICE for some great accounts of the symposium and field trips. https://www.igsoc.org/ice/2017/173/ice173_col.pdf

Glacier Monitoring

  • Out of our 3100+ glaciers only Brewster and Rolleston have ongoing mass balance programmes. 2017 saw the Brewster programme, led by Brian Anderson (VUW) and Nicolas Cullen (Otago), enter its 13th year, while the Rolleston programme, led by Tim Kerr (Aqualinc) and Heather Purdie (UC), entered its 7th consecutive year.  Thanks to all SIRG members who give their time to help with these important field programmes.
  • Ongoing monitoring of Franz Josef Glacier/Kā Roimata o Hine Hukatere (Brian Anderson) and Fox Glacier/Te Moeka o Tuawe (Heather Purdie & Brian Anderson) indicate that Franz has been slowly advancing since December 2016, and while the advance is small so far, the glacier continues to thicken upstream. In a similar vein, Fox is starting to thicken upstream, although this signal has not yet stimulated any action at the terminus.
  • The NIWA EOSS programme is now into its 40th consecutive year. This is an extremely valuable monitoring programme and database, and we hope that it continues for another 40 years!
  • Sabine Baumann (Technical University of Munich) has been working with a number of SIRG members to update the NZ Glacier Inventory which will be presented at AGU in December.


Special congratulations to Andrew Mackintosh on his promotion to Professor of Earth and Climate Sciences at Victoria University.

 Funding Success

  • Dan Price (UC) has been awarded a Marsden Fast-start for research on Antarctic sea ice thickness.
  • David Prior (Otago), Huw Horgan (VUW), Christina Hulbe (Otago), and colleagues, have had Marsden success for research aiming to develop new flow laws for ice sheets.
  • Andrew Mackintosh (VUW), Brian Anderson (VUW) and colleagues have been awarded Marsden funding to explore whether a previous collapse of the Antarctic Ice Sheet caused abrupt climate change in the Southern Hemisphere.

Check-out the Royal Society website for full details of these new projects  https://royalsociety.org.nz/what-we-do/funds-and-opportunities/marsden/awarded-grants/marsden-awards-2017/

  • A number of SIRG members have been successful securing funding for various other projects including (but not limited to)  Ian Fuller (Massey), Sam McColl (Massey) and colleagues have received funding from the Brian Mason Scientific and Technical Trust for research on the response of the Franz Josef and Fox Glacier valleys to climate variability and glacier retreat. Heather Purdie (UC), Tim Kerr (Aqualinc) and colleagues also secured Brian Mason funding to help reinvigorate snow research at Broken River ski field. David Prior and colleagues received a University of Otago Research Grant to improve understanding of mechanical anisotropy of ice. Andrew Mackintosh (VUW) and colleagues secured funding from The Deep South National Science Challenge to undertake research on the impact of climate change to NZ’s frozen water resources. This last project is a truly collaborative effort, bringing together nine NZ snow and ice researchers from a range of NZ institutions!

Recent Theses

  • Edmond Lui, PhD (VUW), Ice Dynamics of the Haupapa/Tasman Glacier Measured at High Spatial and Temporal Resolution, Aoraki/Mount Cook, New Zealand.
  • Matthew Vaughan, PhD (Otago), Creep behaviour and acoustic properties of polycrystalline ice.
  • Meike Seidemann, PhD (Otago, submitted). Microstructural evolution of polycrystalline ice during non-steady state creep.
  • Michelle Ryan, MSc (UC), Characteristics of the Ross and Southern McMurdo ice shelves as revealed from ground-based radar surveys.
  • Ekki Scheffler, MSc (UC), Tide induced velocity fluctuations in the grounding zone of Darwin Glacier, Antarctica, revealed by GNSS and SAR satellite imagery.
  • Sam Taylor-Offord, MSc (VUW), Seismic and Geodetic Observations of Accelerated Sliding at Tasman Glacier, New Zealand.
  • Merijn Thornton MSc (VUW, pending) The Response of Brewster Glacier to Five Decades of Climate.


There have been a number of excellent publications by our SIRG members this year; too many to list here. Below is a selection of publications from some of our SIRG post-graduates. I will forward all the other citations SIRG members sent to me to Tim Kerr, who maintains the SIRG Bibliography. Please remember to send Tim your citations so that he can keep our SIRG page up-to-date. https://sirg.org.nz/about/bibliography/

  • Vaughan, M., Prior, D. J., Brantut, N., Jefferd, M., Mitchell, T. M., and Seidemann, M., 2017, Insights into anisotropy development and weakening of ice from p-wave velocity monitoring during creep. J. Geophysical Research. DOI: 10.1002/2017JB013964.
  • Wild, C.T., Marsh, O.J., Rack, W. (2017). Viscosity and elasticity: a model intercomparison of ice-shelf bending in an Antarctic grounding zone, Journal of Glaciology, 63(240), 573-580.
  • Lauren J. Vargo, Brian M. Anderson, Huw J. Horgan, Andrew N. Mackintosh, Andrew M. Lorrey, and Merijn Thornton. Using Structure from Motion photogrammetry to measure past glacier changes from historic aerial photograph. Journal of Glaciology (accepted).

 So there you have it, some 2017 SIRG highlights, and an email that has hopefully not been so long that you have not made it to this sentence!

I know there will have been other publications, funds awarded, and news, which I have missed. Please accept my apologies for any omissions.

To keep us all up-to-date, make sure you come along to SIRG 2018 at Mt Hutt Retreat, Methven, in February J

 Best wishes for your research/holiday season….

 Ko te pae tawhiti whāia kia tata, ko te pae tata whakamaua kia tīna

Seek out distant horizons, and cherish those you attain


 (as national correspondent for the NZ branch of the IGS (SIRG)

Dr Heather Purdie

Pūkenga Matua

Department of Geography

University of Canterbury Te Whare Wānanga o Waitaha

Private Bag 4800


New Zealand

+643 3694131