[taspeotis]

I used to live in Brisbane which had two "one in 100 year" floods in relatively quick succession: 2011 and 2022. When the second one came there was some talk about communicating the risk more effectively. Instead of saying "one in 100 year" it would be better to say there is like, a 0.2% chance of major flooding every year.

[OJFord]

In what sense is 'one in 100 year' equivalent to '0.2% every year'? With the latter you'd expect 0.2 of them in 100 years?

(Totally agree the phrasing is misleading to the layman though, which is really the only reason for it to exist anyway, in an attempt to be more relatable.)

[taspeotis]

Sorry I was picking a hand-wavey number out of thin air.