Average Recurrence Interval of Extreme Rainfall in Real-time

ParzybokArticles, Disasters, Extreme Weather Theme, Original

Image of Average Recurrence Interval (years) of the maximum rainfall in a 24-hour period during the period February 17-24 2004 storm across the North Island of New Zealand (Natural Hazards Centre, 2004).

Cropped image of Average Recurrence Interval (years) of the maximum rainfall in a 24-hour period during the period February 17-24 2004 storm across the North Island of New Zealand (Natural Hazards Centre, 2004).Knowing how much rainfall fell at a particular location during a certain amount of time is useful, but expressing the rarity of rainfall in terms of a “return period” provides an objective and useful perspective of the rainfall. Average recurrence interval (ARI) maps of rainfall provide information that is analogous to the 100-year flood, but for rainfall instead.