"The fifteen all-hazards National Planning Scenarios are an integral component of DHS's [Department of Homeland Security] capabilities-based approach to implementing Homeland Security Presidential Directive 8: National Preparedness (HSPD-8). The scenarios serve as the foundation for the development of homeland security tasks, target capabilities, and standards and performance metrics against which capabilities and tasks will ultimately be measured. The scenario-derived capabilities and standards serve as a basis for assessing national preparedness; help guide Federal preparedness assistance to State, local, and tribal governments; and assist in development of national exercises and training programs."
United States. Federal Emergency Management Agency: http://www.fema.gov/