Side Flash
Definition
A secondary lightning discharge from the primary lightning channel to a nearby conductor, caused by potential difference between the strike channel and the conductor; can ignite adjacent materials and damage electrical equipment remote from the direct strike point.
- Cause
- Potential difference between the primary lightning channel and a nearby conductor
- Nature
- Secondary discharge, not the direct strike itself
- Ignition risk
- Can ignite adjacent combustible materials
- Damage pattern
- Can damage electrical equipment remote from the direct strike point
Common questions
Why does a side flash matter to a fire investigator working a lightning-origin claim?+
A side flash can start a fire or damage wiring at a location noticeably distant from where the lightning actually struck, so an investigator who only looks for damage directly under the strike point risks missing or misattributing the true ignition source unless side flash pathways are also considered.
How is side flash damage distinguished from a direct lightning strike at the scene?+
A direct strike typically shows a single dominant entry point with the most severe localised damage, while side flash damage appears as a secondary, often less severe discharge path branching from that point toward a separate conductor, sometimes with a visible gap or arcing signature between the two.
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