Extreme Weather Event (EWE)
A subset of "Hazard" and "Threat" to CI comprise Extreme Weather Events (EWE) which causes a CI disruption or, even more often, a Common Cause Failure of multiple CI.
EWE comprise:
- long duration drought
- extreme precipitation in a short period of time (e.g., flash floods, water bombs)
- (extreme) cold wave / cold snaps / ice & snow storms
- (extreme) heat wave
- extreme wind (hurricanes, tornadoes, Derecho, etc.)
Contents
Definitions
International Definitions
IPCC
Definitions of “rare” vary but an EWE would normally be as rare or rarer than the 10th or 90th percentile’
National Definitions
Australia
Definitions of rare vary, but an extreme weather event would normally be as rare as or rarer than the 10th or 90th percentile of a probability density function estimated from observations.
Moreover, Australia has defined severe weather:
Severe weather is often associated with extreme convective weather (tropical cyclones, tornadoes, severe
thunderstorms, squalls, etc.) and with storms of freezing precipitation or blizzard conditions.
United States
NOAA
The U.S. National Oceanic and Atmospheric Administration (NOAA) uses a definition of extreme weather based on an event's climatologically-expected distribution. An event is called extreme if occurs, for example, only five per cent or less of the time. NOAA notes, however, that the exact choice of cut-off of the climatologically probability value used in the definition is somewhat arbitrary. A simple example of extreme weather is therefore when the temperature drops to a level which occurs less than five per cent of the time, say below -20 C. Extreme events, by definition, are rare.
Standard Definition
Discussion
See also
