1996 Western US cascading blackouts
Two major cascading power outages hit the western United States within weeks of each other, cutting power to millions of customers across multiple states and Canadian provinces.
The damage was public. The root cause was preventable.
Two major cascading power outages hit the western United States within weeks of each other, cutting power to millions of customers across multiple states and Canadian provinces.
What the software actually got wrong
Investigators found that grid operators' real-time monitoring and alarm software did not give a clear enough picture of transmission line sagging and loading conditions in hot weather, so operators did not recognize how close the system was to a cascading collapse until it was already underway.
Investigators found that grid operators' real-time monitoring and alarm...
Investigators found that grid operators' real-time monitoring and alarm software did not give a clear enough picture of transmission line sagging and loading conditions in hot weather, so operators did not recognize how close the system was to a cascading collapse until it was already underway.
Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.
Beyond code coverage and "shall" testing
Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.
Surfaces this before code exists
Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.
Connects the failure mode to the hazard
Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.
Find the overlooked root causes before they ship.
Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.