Avalanche Incidents in New Zealand

New Zealand is a land of diverse and dramatic landscapes. From the rugged coastline to the highest mountain peaks and all the variety in between, there is no other place on Earth quite like Aotearoa.

Spoilt for adventure opportunities that rival the world's best and with a culture of time spent in our natural landscapes, it is no surprise that New Zealand's mountains are a popular playground for alpine recreation. Whether it is tramping, hunting, mountaineering, or ski touring, there's something for everyone. However, incidents can occur when dealing with the challenges of this environment. 

From 1998 to 2023, comprehensive data has been collected, capturing critical information on avalanche incidents, patterns, and contributing factors. This research provides valuable insights into the dynamic nature of avalanche danger, helping to improve safety measures, inform public advisories, and guide backcountry users.

By analysing trends over this 25-year period, we can better understand the evolving risks in New Zealand's unique mountain environments, driving advancements in forecasting, education, and response protocols.

This story presents some of the key findings. Please note, interactive elements and graphs are best viewed on desktop.

The data MSC uses comes from a range of sources. Most of it is sourced through partnerships with government agencies and complemented by additional data from specialised industry tools and public observations.

MSC would like to acknowledge contributions from the following organisations and individuals. A summary of their input is below.

This analysis includes avalanche incidents that are either accidentally triggered by humans or naturally occurring but include human involvement. Key markers for inclusion are incidents where a person was caught, buried (partially or fully), injured, or killed.

Witnessing an avalanche without being directly involved is not defined as an avalanche ‘incident’ for this research. Avalanches triggered intentionally through ski field mitigation or control work are also not included, unless they resulted in a person being caught or buried.

Both recreational and workplace/commercial activities are included to ensure a comprehensive dataset of backcountry avalanche incidents and fatalities involving humans.

Over the 26-year period, the number of avalanche incidents has varied significantly from year to year. There was a notable spike in 2019 with 58 reported incidents, the highest recorded in the dataset. Despite the fluctuations in incident numbers, it is pleasing to note that no fatalities have occurred in the previous five years from 2019 to 2023, underscoring the positive impact of a collective effort, ongoing education and implementing safety measures to mitigate the worst outcome.

Note: fatality numbers are included in the total incidents per year. 2011 does not have complete data for avalanche incidents due to file management changeover; however, the zero fatalities statistic is accurate.

The data captured as part of these incidents is, in most cases, extensive, and the list of findings is comprehensive. Through this story, we will share key findings in two parts.

Part One will focus on all avalanche incidents examined by:

• Time: month and time of day
• Location
• Triggers by activity type
• Avalanche characteristics - elevation, aspect, slope angle and size
• NZAA forecast danger rating
• Demographics

Part Two will focus on avalanche fatalities examined by:

• Activity at the time of the event
• Location
• Cause of death
• Group status at the time of the event

Continue scrolling to see the key findings.

As expected, the majority of incidents occur during the winter and spring period, from August to October. Interestingly, September marks a 90% increase in incidents from August, signaling either a more sensitive snowpack as the season progresses or more users in the backcountry, or a combination of both.

As the temperature warms up and the sun plays more of an influence on the snowpack, avalanche incidents are more likely to occur. The late morning and early afternoon, between 11:00am and 3:00pm is the most common time. This time period also represents the time of day when the highest density of people are recreating in avalanche terrain.  

Avalanche incidents in New Zealand are most commonly reported in the Southern Lakes regions of Queenstown (213 incidents), followed by the neighbouring Wānaka region (145 incidents). This is likely due to the combination of the Southern towns receiving comparatively high snowfalls and a diverse user group incorporating recreationalists, commercial operators offering activities such as heliskiing, and mountaineers/climbers.

The proximity of popular ski resorts such as The Remarkables, Cardrona and Treble Cone to challenging, uncontrolled backcountry terrain makes it easy for both locals and tourists alike to venture into areas with heightened avalanche risk. The same can be said for The Craigieburn’s (105 incidents) and Tongariro (77 incidents).

Skiers and snowboarders triggering an avalanche accidentally make up the majority of reported avalanche incidents. However, there may be some reporting bias. Historically, skiers and snowboarders often report incidents to patrol staff at the nearby ski field, allowing for the incident to be captured by the InfoEx. Climbers and trampers don't usually access the backcountry via ski fields and, therefore, don't report incidents in the same fashion.

Since the development of the Public Observations tool in 2018, MSC has empowered backcountry users with the ability to report avalanches online, both by name or anonymously. A culture of using this platform for information sharing among recreational backcountry users has grown exponentially over the past few years, particularly amongst backcountry skiers and snowboarders. We hope that this increased engagement will continue and will be utilised more readily by mountaineers and climbers in the future, to reduce any reporting biases.

(Note: A remote event is defined as one occurring at some distance, typically > 5 m, from the probable trigger.)

The data shows that the majority of avalanche incidents in New Zealand occur between 1500 and 2000 metres in elevation, with the most frequent elevation band being 1750-2000 metres, accounting for 315 incidents. This trend aligns with the fact that most of New Zealand’s easily accessible backcountry terrain for skiing and snowboarding (illustrated as the primary activity for avalanche incidents in the previous figure) is located adjacent to ski fields, which are most common within these same elevation bands. This data is reflective of the higher volume of users.

The most likely aspect for an avalanche incident to occur is on a southern eastern aspect, which correlates with New Zealand's geographical and meteorological context. These aspects are more likely to be wind-loaded by our prevailing north-westerly winds, and weaknesses in the snowpack are more likely to persist on polar aspects in the southerly quatre. Anecdotally, aspects in the southerly half are where the best quality skiing or snowboarding occurs too, and where snow is most likely to persist during the spring and summer.  

Avalanches are most likely to occur on slopes with angles between 30 and 40 degrees, most notably between 36 and 40 degrees. A number of avalanche incidents are reported on slopes outside of this range. This data is consistent with international patterns and, in turn, what is taught in avalanche courses.

All those avalanche incidents reported at an angle below 20 degrees were remote triggered events. Whilst difficult to ascertain, it is the authors belief that the reported slope angle of these remote events was at the trigger point rather than the angle of the start zone.

Slab avalanches account for the greatest number of incidents, with 663 incidents attributed to slab avalanches in Aotearoa. Whilst some of the data lacks enough detail to determine the specific type of avalanche, it is clear that wind slab avalanches are the most prominent avalanche type relating to incidents in NZ.

As a reminder, these are only reported avalanches that were unintentionally triggered or where people have been caught; this is not a reflection of all observed avalanche activity.

The majority of avalanche incidents have been size 1-2 avalanches. This size characteristic varies from what is seen internationally. This could indicate recreational backcountry users are following avalanche advisory travel advice and not going into the backcountry when the potential for large avalanches exists.

The NZAA provides public avalanche advisories for 13 regions across the country. These forecasts are written specifically for recreational users of the backcountry, therefore no commercial incidents are included in this analysis.

The data highlights a few key points regarding avalanche incidents, relative to the forecasted danger rating:

1. Extreme and High danger ratings account for a very small number of incidents. It is promising to see that people are taking appropriate precautions and avoiding avalanche terrain when conditions are particularly dangerous.
2. Most avalanche incidents occur during Moderate and Considerable danger ratings, which together account for 66% of incidents. This emphasizes that these danger levels should not be underestimated—avalanches are still common when conditions seem manageable.
3. Low danger ratings account for 13.7% of incidents, reinforcing an important safety message: "Low danger does not mean no danger". Although unlikely at this rating, human triggered avalanches can and do happen.
4. Lastly, the "Center closed/no forecast" makes up 17.78% of incidents. This accounts for the majority of mountaineering and tramping incidents, outside of the forecasting season or outside of forecasting regions.

Overall, the data highlights that most avalanche incidents happen at the Moderate danger rating, and that even Low danger requires caution. In recent years, the NZAA has begun providing avalanche forecasts to better cater to mountaineers and trampers for extended periods during the late spring and early summer, as well as year-round forecasting in the Aoraki/Mt Cook region.

Men are far more likely to be involved in an avalanche incident, even when accounting for differences in participation numbers. This data follows what is seen internationally.

Individuals in the 26 to 35 year age range make up the majority of individuals involved in avalanche incidents. This data reflects a similar pattern to what is reported internationally. However, there are enough 'unknown' or unreported age groups to warrant caution in drawing strong conclusions for the age of people involved in avalanche incidents.

Continue scrolling to view the findings relating specifically to New Zealand's 27 avalanche fatalities that occurred between 1998 and 2023.

The interactive map below indicates the approximate location of these avalanche fatalities. You can zoom in and hover over the pin (on a desktop) to reveal the location, activity and date of the fatality.

From this dataset, there is a roughly even split between trauma and asphyxiation/suffocation as the primary cause of death. The number of 'unknown' causes of death warrants caution in making any strong conclusions however.

The vast majority of avalanche fatalities have been travelling in a group rather than solo. The exact group size at the time of the avalanche is not known.

The data used in this research has been through a comprehensive review to ensure the accuracy of the analysis, remove duplicate reports and to ensure all reported incidents qualify as ‘human-involved’, as detailed in the methodology.

However, this study faces some limitations due to gaps in data collection and reporting.

Firstly, it is likely that some avalanche incidents in New Zealand are not reported, particularly those in remote areas or minor incidents where no significant harm occurs. This underreporting can lead to an incomplete dataset, affecting the accuracy of the overall total events.

Secondly, there are a small number of examples where the available data may lack precision or completeness, given the complex nature of avalanche phenomenon and varying skill levels of those submitting reports.

Any variables associated with unreliable reporting have been managed to the best of our ability. We feel that the trends seen in the data and overall analysis are accurate enough to draw reasonable conclusions and provide enough detail to illustrate the bigger picture of avalanches in Aotearoa.

Accurate and timely reporting of avalanche incidents and fatalities is critical to continue this research and to provide these insights to the industry.

Avalanches are an ever-present danger in the alpine backcountry. Each year thousands of people participate in backcountry snow sport activities across NZ, either consciously or unconsciously exposing themselves to the danger of avalanches.

The most common characteristics of human-involved avalanche incidents in NZ include:

• Located in the Queenstown region, during the winter or early spring
• Occur on southeasterly aspects, between 1750-2000m elevation
• Involve size 1-2 slab avalanches, most commonly wind slabs
• Triggered by a backcountry skier, accidentally
• For recreational incidents, the majority are triggered at a 'Moderate' NZAA Danger rating
• Mostly involve males between the ages of 26 and 35

The comparatively large number of avalanche incidents when accounting for our small population highlights the ongoing need for comprehensive public avalanche education and awareness to continue to reduce the likelihood of incidents.

Thankfully, New Zealand does not experience the same number of avalanche fatalities as other developed nations. However, when compared with our population size and anecdotal levels of participation, the number of fatalities over the past 26 years is similar. The potential for tragedy is always present, and a continued reduction in avalanche incidents is always desired. 

Staying safe in avalanche terrain

The following MSC resources are available to learn more about avalanche safety:

•  NZ Avalanche Advisory 
•  Free online beginners avalanche course 
•  Find an avalanche course provider 
•  Mountaineering information 
•  Backcountry Snowsports information 

MSC's research project  Above and Beyond,  believed to be a world-first, explored the culture, behaviours and attitudes of the New Zealand mountaineering community towards avalanche safety. 

The research team identified 16 recommendations aimed at improving avalanche safety amongst the mountaineering community, an integral component being increased information sharing and more open dialogue. The following are examples of how, without criticism, we can learn from incidents, improve avalanche education and inform decision-making by sharing reflections with the community. View a selection of recent avalanche stories below:

 Spring Skiing Avalanche on Cascade Saddle  | November 2023

 Size 3 slab avalanche incident, The Remarkables backcountry  | August 2023

 Rescued Ice Climbers admit pushing limits too far  | July 2023

 Avalanche fatality results in safety recommendations  | Nov 2018

 A climbers lucky escape  | July 2020

MSC wishes to continue to facilitate the sharing of these stories, to benefit the entire alpine community. If you have details or reflections on an incident that you would like to share, please  get in contact .

Photos used within this story include captions noting the photographer. All images are used with permission and must not be reused without the expressed permission of the Mountain Safety Council.

This story was created by the Mountain Safety Council, 2024. All rights reserved.