Australian snow pack in decline since 1957

Anyone who is paying attention to the state of our winters knows that they are getting more erratic. Often they start later (it’s a rare thing to ski on natural snow on opening weekend) and subject to more rain events, with big impacts on snow pack. While our climatic patterns go through natural wetter and drier cycles, climate science tells us that these patters will become more extreme, with less overall snow and shorter seasons.

Anecdotes and personal experience are one thing. But when did the snow pack actually start to decline?

While all resorts track snowfall, the benchmark of snowfall in Australia over time comes from Spencers Creek, at a site at 1,800 metres above sea level, in the Main Range of the Snowy Mountains. The following article comes from ABC Rural and gives a sense of the decades worth of data that is available from this site, and the process of getting the data. The measuring site was originally established to give the Snowy Hydro managers a sense of what water was trapped in the snow pack and hence how much water would be released in the spring. As skiers and riders, what it gives us is a long term summary of the trends in snowpack over the past six decades.

The take home message is that, overall, snowpack has been declining for decades and unabated climate change will make that worse. While the article does not drill into this issue in detail, previous analysis of this data by Terry Giesecke suggests that:

“There has been a downwards trend (in snow pack) from 1957 to 1989. It then goes up dramatically for about four years, before resuming a downwards path”. This research suggests that the increase in snow depth between 1990 and 1994 could have been due to global cooling which occurred as a result of major volcanic activity in the Philippines in 1991. Using data collected up until 2016, it also notes:

“There is evidence of further decline in the first 16 years of the 21st century.”

How do we keep track of record snowfalls in Australia? It all happens at remote Spencers Creek

By Sarina Locke, Catherine McAloon and Bianca Gurra

Snow depth measurements taken at a remote location in the Kosciuszko National Park have kept track of the Australian snow seasons and charted record-breaking snowfalls for more than six decades.

Midway between Perisher Valley and Thredbo, Spencers Creek has been visited by weather observers every week during winter since the mid-1950s, when the Snowy Hydro scheme was being constructed.

In the early days it would take workers on cross-country skis two days to reach the location, camping out at mountain huts along the way.

Nowadays, weather observers employed by electricity generator Snowy Hydro access Spencers Creek by snowmobiles, but they still use similar equipment to that used decades ago to take measurements of snow depth that provide a crucial record of Australian snowfall.

The data, along with measurements from other sites in the national park, is used by Snowy Hydro to figure out how much water there is in the snow pack.

Snowy Hydro manager of weather and water, James Pirozzi, said snow melt provided about two thirds of inflows into Snowy Hydro’s 16 large dams, which in an average year receive about 3,000 gigalitres of water that is used to make hydro energy.

“We need that [snow depth information] to understand what sort of inflows we are going to receive into our dams, so that we can do some forecasts on our energy production over the next year,” Mr Pirozzi said.

Snow data through the decades

Snowy Hydro’s measurements, which are published online each week during the winter months, are also relied on by ski enthusiasts and weather watchers.

This week, there was much speculation as to whether the snow storm that hit the Australian alps last weekend would make a dent in the record books.

Measuring the snow depth at Spencers Creek on Thursday, Mr Pirozzi said while it had been a good fall, it was by no means a record.

“We ended up with 179 centimetres after that bit of snow we got over the weekend, topped it up by about 60 centimetres, so it’s looking around about just above average.”

In comparison, in 1984 — a year weather watchers recall for a huge dump of snow — records from Spencers Creek show snow depth increased by more than a metre from 107.6 centimetres on August 16 to 215.5 centimetres a week later.

Other years cited for big snow dumps include 1964, when snow depth measured at Spencers Creek increased more than 1.5 metres in a fortnight to 308 centimetres, and 1981, when overall snow depth reached 360 centimetres in late August, adding more than a metre over a couple of weeks.

Insight into a changing climate

As well as providing weekly updates throughout the season, the data collected at Spencers Creek gives a picture of how snowfall in the alpine region has declined in recent decades.

In research published earlier this year, the CSIRO noted there had been a significant decline in the past 60 years in the southern slopes and Murray-Basin areas. ...