Methods/Joint Probability Method
Joint Probability Method (JPM) for Coastal Flood Hazard Assessment
The Joint Probability Method is a statistical framework for estimating the annual exceedance probability of coastal flood levels — primarily storm surge — at a given location. Rather than relying on a historical record of observed surge heights, JPM builds surge-frequency relationships from the joint probability distributions of the meteorological parameters that generate surge, pairing them with hydrodynamic numerical models such as ADCIRC or SLOSH. In the U.S., JPM is the standard approach recommended by USACE and FEMA for flood-insurance studies and by the NRC for coastal-flood hazard assessment at nuclear facilities.
Return to Methods and Tools. | EPRI technical point of contact: Chris Rochon (CRochon@epri.com)
Date last reviewed: 2026-05-07