Cascading Outage

A sequence of events in which an initial disturbance triggers dependent component outages.

Last Updated:  June 20, 2025

Definition by an IEEE Working Group

Source:

A cascading outage is a sequence of events in which an initial disturbance, or a set of disturbances, triggers a sequence of one or more dependent component outages:

  • In some cases they halt before the sequence results in the interruption of electricity service
  • In many case, cascading outages have resulted in massive disruptions to electricity service: Northeast blackouts in 1965 and 2003, New York City blackout in 1977, two WECC blackouts in 1996, Brazil blackout in 2009, WECC blackout in 2011, etc