‘100-Year Floods’ Happen More Often Than People Think

By | April 22, 2016

  • April 22, 2016 at 9:02 am
    Yogi Polar Berra says:
    Like or Dislike:
    Thumb up 3
    Thumb down 0

    100 year floods are happening every 100 months. Why can’t we go back to the old schedule?

    • April 22, 2016 at 10:13 am
      confused says:
      Like or Dislike:
      Thumb up 3
      Thumb down 7

      (cough) climate change (cough)

  • April 22, 2016 at 4:54 pm
    insurance_guy says:
    Like or Dislike:
    Thumb up 0
    Thumb down 0

    You can calculate the probability as a binomial coefficient. 1-0.99^100 = 63.4%. This means that there is 63.4% probability of one major flood occurring in a hundred years.

    • April 22, 2016 at 6:47 pm
      insurance_guy says:
      Like or Dislike:
      Thumb up 0
      Thumb down 0

      Sorry math buffs, I meant to say binomial distribution. The article says its 67%. I believe this difference is due to the fact that he probably used software.

      • April 25, 2016 at 10:28 am
        Other_person says:
        Like or Dislike:
        Thumb up 1
        Thumb down 0

        Poisson distribution might be more appropriate here.

        • April 25, 2016 at 11:50 am
          insurance_guy says:
          Like or Dislike:
          Thumb up 1
          Thumb down 0

          You’re right. But there is more than one way to skin a cat.

          • April 25, 2016 at 8:44 pm
            Yogi Polar Berra says:
            Like or Dislike:
            Thumb up 1
            Thumb down 0

            Ahem! the main point of the article is that the probability is shifting higher, not constant at 1% per year, per the OP in this thread. If my whimsical suggestion that these are now occurring at 100 month intervals, 12% per year frequency would be more appropriate…. for now.

            The Binomial or Negative Binomial distributions are only (realistically) applicable accurately when the probability of loss parameter is constant.

            An application of the Poisson distribution for the time dependent frequency would need to reflect changing mean value parameters.

            It’s time to cue up David Bowie’s “Changes”.



Add a Comment

Your email address will not be published. Required fields are marked *

*