[epitomix]

I think that this statistic only makes sense if it is specific to the location. Otherwise, it is useless for planning purposes. If it is specific to the location then the birthday paradox does not apply.

Interesting note, this is Houstons third 500-year flood in three years [1].

[1] -https://www.washingtonpost.com/news/wonk/wp/2017/08/29/houst...