It's not hard to predict the past
Briggs on Gore on snowstorms:
It takes no effort to point to untoward events after the fact and say, Jean Dixon-like, “See! More evidence that my theory is right!” If it is true that global warming will cause the Northern Hemisphere to experience cooler temperatures, then say so in advance. Don’t bustle to the camerasafter things go wrong if you did not, or could not, say that they would in advance.
Vague predictions like “There will be snowstorms and rumors of snowstorms” do not count and are not evidence that the end is near. Take heed that no man deceive you. It is, after all, perfectly possible to forecast that there will be, say, “15% more snowfall in the 2010-2011 Northern Hemisphere winter”, or that “There will be at least three more Pacific ocean typhoons in 2011 than there were in 2010″, and so forth.
What is absurd is to point to a typhoon/cyclone/hurricane/snow storm after it has occurred and say that, “I could have predicted that if I wanted to. I chose not to because, among other reasons, I was busy. But that storm certainly indicates that my theory of climate change is true.”