A major power outage occurred in Western North America on August 10, 1996. In this paper, the authors describe the simulation of this disturbance using a transient stability program. Initially, the sequence of events was simulated using the standard WSCC dynamic database, and the simulations did not agree with the disturbance recordings. Several model additions and data modifications were made before the simulations approximated the disturbance recordings. These model changes are discussed in the paper.