Predicting extreme rainfall events
One of the important roles of weather forecasting is to help warn society towns and communities about rare and extreme events, such as floods, that can cause severe damage and losses.
Understanding rare rainfall events is important, so that infrastructure like levees, dams and bridges can be built to help keep communities safe.
The Department of Water uses the CRC-FORGE method to predict extreme rainfall estimates for Western Australia. It is widely used by civil engineering professionals and provides information about where the rain will fall, how much might fall and the annual probability of rain.
The Department of Water's seasonal design rainfall database indicates Annual Exceedance Probability (AEP) of 1-in-50 through to 1-in-2000 for durations of between 24 and 120 hours.
The database should be used in conjunction with design rainfall information available from the Bureau of Meteorology.