By Gerg, on July 30th, 2013 
The definitive report on the effect of climate change on Australian snow is undoubtedly the CSIRO/ANU study of Hennessy et al (The impact of climate change on snow conditions in mainland Australia, K Hennessy, P Whetton, I Smith, J Bathols, M Hutchinson and J Sharples, CSIRO Atmospheric Research, August 2003). It’s much-cited, and formed the basis of the snow section (5.2.6) in the authoritative Climate Change in Australia report of 2007.
Amazingly the Hennessy report is 10 years old next . . . → Read More: Hennessy et al, 10 years on
By Gerg, on July 26th, 2013 Wow, if we need to post about little weather systems like this thing we really are having a crap season … maybe 10 cm. The interesting thing is that the resort skiing seems to be holding up well (at least low to intermediate) — on desperately thin natural snow. Snow making has come a long way in the last decade, particularly with the introduction of elevated low-air nozzles. We’re looking at the future of Australian skiing, right now.
Update (28/7): . . . → Read More: 2-3 August 2013
By Gerg, on July 17th, 2013 
While most snow depth interest tends to focus on the Spencers Creek site between Perisher Valley and Thredbo, Snowy Hydro Limited kindly publishes the full snow depth records for three of their sites on-line*:
Spencers Creek, at 1830 m elevation, near Charlotte Pass Deep Creek, at 1620 m elevation, near Cabramurra, and Three Mile Dam, at 1460 m elevation, near Kiandra.
Together these cover the range of snowpack elevations and provide a more nuanced view of how our snow varies . . . → Read More: Adding Deep Creek
By Gerg, on July 16th, 2013 What’s next? The NCEP GFS ensemble is suggesting action Sunday week. It is smeared out in time, but appears moderately strong — all those blue contours near Victoria. Seems we are settling into the usual weekly storm pattern of our winter.
Update (20/7): Just coming up on EC now, a day later than at GFS. Moved dates forward 1 day.
Update 2 (22/7): This system is now well up on EC. Unfortunately that model is now showing some initial rain . . . → Read More: 28-30 July 2013
By Gerg, on July 13th, 2013 
A popular internet meme runs something like “melt was similar back in…”, usually referring to some arbitrary period in the 1920s or 30s. Well, unsurprisingly, there really are quite good records from then, and, unsurprisingly, they show nothing remotely like current ice conditions:
The animation is drawn from the Danish Meteorological Institute’s sea ice maps for August in each year from 1920 to 1939. The red marks show actual records of ice conditions and the white area . . . → Read More: More on northern sea ice
By Gerg, on July 11th, 2013 According to most models a follow-up event is coming mid next week, with lots more rain initially. But this one looks to have snow in the tail, maybe as much as 30 cm Thursday into Thursday night, with more to come into the following weekend.
Update: The snow action in this event has drifted later: more like Friday night into Saturday; 30 cm is looking very optimistic.
Update 2 (14/7): Back to thinking 30 cm is possible, Friday night through . . . → Read More: 18-22 July 2013
By Gerg, on July 9th, 2013 
PIOMAS northern sea ice volume
The northern sea ice melt season is well underway and PIOMAS has updated, so it’s time to review status. I follow the PIOMAS series because it tracks ice volume, and it seems to me that total ice mass (or volume) should be the most meaningful and coherent indicator.
The graph shows two traces:
The light-blue-filled total ice volume curve, plotted on the left axis. That varies through a huge range with the annual . . . → Read More: Northern sea ice update
By Gerg, on July 6th, 2013 The Antarctic Oscillation (AAO) is the strongest single effect in the statistical snow prediction model. AAO is a measure of how tightly the circumpolar flow blows around the pole. A loose pattern (negative AAO) means polar storms track further north and are more likely to bring us snow. The AAO tends to moves in regular short term cycles (weeks), but it also exhibits longer term swings with considerable coherence (months). The recent longer term trend has been strongly positive (bad), . . . → Read More: AAO swings our way
By Gerg, on July 6th, 2013 The NCEP ensemble of GFS is suggesting another snow event next weekend, and I find it to be one of the more reliable guides at this range. Unfortunately the EC model (by far the best long range deterministic model) has been showing some pretty nasty tropical feed, indicating rain, not snow. We will have to wait for updates.
Update: This is now clearly a rain event, unfortunately. With the low stalling in the bight, there’s a chance the worst . . . → Read More: 13-15 July 2013
By Gerg, on July 4th, 2013 
Are we on track to come in below our worst season ever, 2006?
(Click refresh on your browser for the latest plot.)
Probably not … 2006 was an El Niño year, with the June-July-August average SOI of -10. This year will be neutral (SOI near zero). 2006 also had a mildly positive Indian Ocean Dipole (bad for snow); this year it should be slightly negative.
There’s enough moisture around to expect some decent falls. We just might have to . . . → Read More: Another 2006?
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