Final answer:
A disaster or catastrophic event that overwhelms a community and needs a multiple agency response can be classified as involving international externalities, such as a pandemic.
Step-by-step explanation:
An event that requires resources beyond the capability of a community and requires a multiple agency response is a disaster or catastrophic event. Such events often involve international externalities, which are externalities that cross national borders and cannot be resolved by a single nation acting alone. An example of this could be a pandemic, which is an infectious disease epidemic that spreads across multiple populations or continents, or even worldwide, like the COVID-19 pandemic. A disease outbreak can become a pandemic if it spreads extensively and outstrips the capacity of communities to handle the situation, necessitating a coordinated international response.