Have you been wondering why it snowed?

Even Auckland copped a flurry or two. Odd. Climate change is responsible for the cold blast that swept the country and we in turn for that change.
From the comments on a Standard post, Macro explains it well:

Macro …

30 August 2011 at 5:21 pm

And you know why grumpy?
“The severe southerly outbreak this week is also being blamed on changes in the polar vortex – the ring of westerly winds encircling the Antarctic.
The Southern Annular Mode (Sam), which measures the strength of the vortex, has been strongly negative this month. That means the westerlies are weaker than normal, allowing polar air to break out and head north towards New Zealand. ”
And what might have caused this??
Well:
to quote Dr James Renwick who is the expert on this..
“National Institute of Water and Atmospheric Research principal climate scientist James Renwick said the Sam was likely to remain negative for the rest of the month before flipping to positive values in September.
“It is very strongly negative right now. [Air] pressures are high at high latitudes, with ridges of high pressure extending towards South America, east of South Africa and towards Hobart, but we have very much lower than normal pressures to the east across the central Pacific,” he said. “So we end up with this big southerly flow, and with this pattern I would expect we would see more of these big highs at high latitudes to the west. That means more southerlies … are on the cards.”
You see these big highs that come across from Australia have to form somewhere and you know what? Yeah! They are the result of a warming world – just as the large depressions are a result of a warming world. That air that raced directly down to Antarctica wasn’t cold on its way down. And to quote the 2nd law of thermodynamics “Heat never flows from a colder to a hotter” so, It lost heat – to Antarctica – and gained heat in NZ dropping snow in Auckland.
Changes in the SAM – it’s part of that which is generically called “Climate Change”.