Definition of a disaster

Answer:

A disaster is if the incident lasts longer than what you have set as your RTO (Recovery Time Objective). In other words, this is when an incident disrupts your activities for a time that is longer than what is acceptable for your business.

In the ISO 22301 Documentation Toolkit you can find this definition in the document "Business Continuity Plan" section "3.4 Plan activation; plan deactivation" (folder 06 in the toolkit).

Regarding scenarios, you can find most common scenarios in the document "Examples of disruptive incidents scenarios" (folder 05).