Definition
In risk management, severity is the measure of how bad the consequences would be if an identified hazard actually resulted in an accident or incident. It is one of the two factors — along with likelihood — used to assess the overall level of risk associated with a hazard.
Plain English
Severity answers the question: if this goes wrong, how bad will it be? It rates the size of the harm — minor, moderate, major, or catastrophic — independent of how often the event might occur.
Context Anchor
Seen when judging flight risks before or during a flight, such as weather, runway conditions, aircraft problems, or a training situation with a student.
Derivation
From the Latin severus, meaning strict or serious. The aviation use keeps the everyday sense of seriousness but applies it specifically to the magnitude of a potential outcome.
Why Pilots Care
It combines with probability to set overall risk level and guides decisions on whether to accept, mitigate, or avoid a hazard.
Grounding Statement
Severity asks, “If this goes wrong, how bad could it get?”
Intuition Check
Do not read severity as the same thing as probability. Severity is how serious the result could be; probability is how likely it is to happen.
Example Sentence 1
When evaluating the risk of flying near forecast thunderstorms, the instructor rated the severity as catastrophic even though the likelihood of an encounter was low.
Example Sentence 2
A minor severity event such as a small paint chip on the wing does not require canceling the flight.