100 year, or 25 or 50 year criteria are probabilites. It's the expected, or the worst expected, events within the next 25, 50, or 100 years. They're based on historical data, but have no real day to day meaning. The next 100 year event could be in 200 years or tomorrow.
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Hope for the best and prepare for the worst.

The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane