Pet theories are the most fun aspect of snow prediction, everyone that has been going to the snow for a few years has their own pet theories. Some may have some loose basis in fact and some are just good fun.
Adelaide 14 degrees and rain If Adelaide is forecast to get rain and the temperature is 14 degrees or less, then the cold wet air is on its way and will fall as snow when it reaches the alps. This one is a good short term predictor.
Canberra 10 degrees and rain If the forecast is for rain in Canberra and 10 degrees celcius or less then it will be snowing in Thredbo down to the village.
One Hundred days after the first frost This one is down to Didi at Dinner Plain. 100 days after the first big frost at Dinner Plain equates to the first big snowfall for the season. This one supposedly worked every year from 2000 - 2005. Unfortunately it didn't work in 2006.
Pelican numbers on the East Coast When pelican numbers decline on the east coast of Australia this is because they are flying inland to a wet interior. A wet interior means that the air mass moving over the continent picks up moisture and hence we have a good season.
Full Lake Eyre' When there is water in Lake Eyre it will be a good year. This may relate to underlying weather conditions that mean that where there is enough precipitation to fill the lake there will be enough precipitation to cause snow. Or it may have something to do with a misunderstaning of the lake effect. Then again, people may think that anything named after the Eyre lift at Perisher must have something to do with snow.
Full Lake George Same idea as Lake Eyre - when there is water in Lake George there is precipitation around, and snow is precipitation.
Self Proclaimed Long Range Forecasters Predict Above Average Season No discernible effect.
New Zealand Theories
High pressure in Hobart When a large cell of high pressure 1020 or more sits over Hobart, this correlates with a strong Southerly flow over the South Island, and snow to low levels.