• The Australian Alps experienced rapid and early loss of snow cover in September of the 2023 snowsports season.
  • The unusually warm and dry weather from June to September contributed to the snow loss.

After a strong start, Australia’s snowsports season came to an early finish, with Australia’s warmest winter on record contributing to rapid snow decline in the alps. As well as being popular for winter sports, the Australian Alps are important for renewable energy generation, hosting the Snowy Mountains Hydro-Electric Scheme. In the Australian Alps, cold weather and snow are generally associated with cold fronts.

During the 2023 winter, a combination of continued human-caused global warming and natural weather systems meant that far fewer cold fronts arrived to bring snow to the region. Instead, high- pressure systems that promote warmer, drier weather were widespread across south-eastern Australia.

The warm, dry winter culminated in a September that was both extremely dry, and the hottest September on record in the Australian Alps. The long-term average September temperature in Perisher Valley is 2.25°C. The 2023 September temperature was 5.85°C, which is 3.6°C hotter than average. September 2023 was also 1.45°C hotter than the next-warmest September on record for Perisher Valley(2013). This hot weather caused a very rapid and early loss of snow cover across the alps.

The rapid snow decline did not only impact snowsports. Water storages in the Snowy Mountains Hydro-Electric Scheme are used to generate renewable energy, and to capture, store and divert water for downstream users in New South Wales and Victoria.

‘The low frequency of cold fronts and warmer-than-average temperatures this winter impacted both natural snowfall, as well as the opportunities for snowfall enhancement via our Cloud Seeding Program,’ says Dr Johanna Speirs, Senior Climate Scientist at Snowy Hydro.

‘Snowmelt and runoff into the Snowy Scheme for June to November were about 60% of the long-term average.’

Fortunately, the Snowy Scheme was designed to operate within a variable climate, and reservoir storages had recently been boosted by the three-year wet period associated with La Niña and negative Indian Ocean Dipole.

We cannot yet attribute this year’s poor snow season to climate change. However, this does not mean that climate change did not play a part – in fact, snow depths have been steadily declining over the past decades, while alpine temperatures have been rising.

Figure 1. Average snow depths at three Snowy Hydro monitoring sites within the Snowy Mountains. Sites arranged by decreasing elevation from left to right. Blue line shows 1957-2022 average snow depth, ribbon shows snow depths in the 10th to 90th percentile, red line shows 2023 snow depth. Source data: Snowy Hydro.

Research contact:
Dr Georgy Falster, georgina.falster@anu.edu.au