Okay folks how did FEMA come up with this metric:
"To fully establish the core capability requirements for the nation in both response and 21 recovery, we need to focus beyond any single threat or hazard. We must recognize that the complex environment of disasters includes cascading events that combined can stress the abilities of our Nation. Therefore, in order to ensure that these core capabilities can be delivered / performed in the shortest possible time and under all conditions, a set of planning factors can be used to create a composite or “meta-scenario” that illustrates the anticipated stresses on our core capabilities. The numbers identified in the meta-scenario were derived from modeling efforts for multiple high impact incidents and reviewing using the strategic national risk assessment. The following summarizes the meta-scenario that will be used to drive national-level response and 29 recovery planning efforts:
There is a no-notice event impacting a population of seven million within a 25 thousand square mile area. The impacted area includes several states across multiple regions. Severe damage is projected to critical infrastructure including essential transportation infrastructure. Ingress and egress options are severely limited. The projected number of fatalities is 195,000 during the initial hours of the event. It is projected that 265,000 survivors will require emergency medical attention. At least 25 percent of the impacted population will require mass care, emergency sheltering, and housing assistance."