Appendix D: Scenario Chronology

The following figure (Figure 12) visualizes the timelines of the Plausible Concurrent Operations incidents as well as the scenarios used in the 2019 National THIRA. For the purposes of this figure, “incident period” is the estimated period where all the agencies involved are engaged in response activities, including efforts to save lives, protect property, and meet basic human needs. The capability targets only include baseline impacts if the 2019 National THIRA scenario occurred while there was an active response or recovery phase for the incident. For example, the impactsofthe Cascadia/SanAndreasandNewMadridearthquakescombinedwithonlya fewimpactsfromthe PlausibleConcurrentOperations, while the Hawaii hurricane impacts combine with several. Dates for the National THIRA scenarios were selected in the following order of preference:

1. A specific date was identified in the modeling FEMA used to estimate impacts.

2. A specific date was not identified in the modeling FEMA used to estimate impacts but was included in a response plan or Regional THIRA scenario.

3. A time when the incident is most likely to occur (e.g., peak hurricane season).

4. A time when the incident is likely to be the most stressful.