Best place for tornado data?

I need to know what is the best online source for tornado data?
I just want the facts not some summery of cold-hard facts about
frequency and locations.

Thanks,
Pedro

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Sun Tzu said, ?If you wait by the river long enough, the bodies of your enemies will float by.?
I said "Build a fire for a man and he will be warm for a day, but set fire to that man and he will be warm forever!"
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