One approach to rating qualitatively is to establish general ranges of
impact for key indicators.
In this example, I have used factors most commonly
reported in media reports: deaths, injuries, extent of property
damage, and the degree to which community services still function.
The range of each factor is variable based on the size of the
community. For example, a
school bus accident that kills 15 and injures 20 in a rural
community might well be a high impact event.
In a major city, the same casualty count may be a normal
weekend evening loading generated by the routine level of urban
violence.
