Measuring snow depth

Ever wondered how Snowy Hydro collect data for measuring snow depth, how they arrive at the final measurements and why all NSW resorts use the same snow depth measurement?

Collecting data
Once a week, typically Thursdays, a couple of hydrographers from Snowy Hydro travel out to Spencers Creek Snow Course to do a snow survey. The snow course is located approx 7 kilometres from Perisher, on the way to Charlotte Pass, and it sits at 1830 metres above sea level, around the same height as the Cruiser area at Thredbo. This snow course consists of seven marker poles, approximately 30 metres apart. At each pole they take a snow sample, using, surprise, surprise…. a snow tube sampler. This cuts a core of snow that they use to record the overall depth and weight of the snow (for snow water content).

The final measurement
The snow depth is read directly off the sampling tube, while the snow weight is calculated by subtracting weight of the empty tube from the total weight of the tube and core of snow. The sampling tube is of a specific diameter, so that one ounce of snow weight is equivalent to one inch of snow water content. The snow density is then calculated by dividing by the water content by the depth. For example, if the water content is equivalent to 30cm and the overall depth is 100cm, the density is 30%. Snowy Hydro record this measurement at every pole and then calculate an average using the results of the seven snow core measurements at the snow course. It’s the average figure, made public by Snowy Hydro, that’s used as the official snow depth from Spencer’s Creek.

A unified snow depth for all NSW resorts
There has always been an overriding myth that snow resorts exaggerate the snow depth. Snowy Hydro have been doing snow surveys at Spencer’s Creek since 1954 for estimating the stored water in the snow pack for spring runoff water volume calculations. It is for this reason that the Spencer’s Creek survey has been adopted as the “official” NSW snow depth by the NSW resorts, therefore the validity of the snow depth measurement at each resort could not be questioned, and snow goers can trust they are receiving factual scientific measurements. For our guests information we have introduced a cumulative snow measure to our reports so you can see how much snow has fallen in 24hours, 48 hours, 7 days and the season.