How They Forecast a Cold Winter

One day in early September the chief of a Native American tribe was asked by his tribal elders if the winter of 2011/12 was going to be cold or mild. The chief asked his medicine man, but he too had lost touch with the reading signs from the natural world around the Great Lakes.
In truth, neither of them had idea about how to predict the coming winter. However, the chief decided to take a modern approach, and the chief rang the National Weather Service in Gaylord Michigan.
'Yes, it is going to be a cold winter,' the meteorological officer told the chief. Consequently, he went back to his tribe and told the men to collect plenty of firewood.
A fortnight later the chief called the Weather Service and asked for an update. 'Are you still forecasting a cold winter?' he asked.
'Yes, very cold', the weather officer told him.
As a result of this brief conversation the chief went back to the tribe and told his people to collect every bit of wood they could find.
A month later the chief called the National Weather Service once more and asked about the coming winter. 'Yes,' he was told, 'it is going to be one of the coldest winters ever.'
'How can you be so sure?' the chief asked.