How to Calculate Flood Probability

A flood can destroy your home and all of your possessions in a single swoop. Predicting flood probability is done by calculating its recurrence interval. The best predictor of future behavior is its past performance. With this in mind, forecasters use recorded weather data to calculate the probability of future flooding. If no floods have occurred in the past, most likely there will be no future flooding. This information can be used to protect your home against such events by designing it for its local climate.

Things You'll Need

• Past weather data
• Calculator

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Instructions

1. • 1

     Determine the total number of years of weather data you have by subtracting the current year by the last year in the data set.

   • 2

     Count the number of years in the data where a flood occurred.

   • 3

     Divide the total number of years by the number of times floods occurred. The result is the average number of years between floods.