Disasters which count
Pandemic
Ai mishap
Terrorism
Famine
Disease
Nuclear strike or accident
Infrastructure collapse
War also counts
Deaths from old age, traffic, etc don't count unless related.
A death by disaster is an unintended (by the victim, at a prior state in time) death. Eg being converted to a cult which causes suicide can still be a disaster.
Since disasters have different time scales (instant vs gradual), it can be hard to quantify. This is how I'd like to do it here: at any starting point in time consider all residents of anxiety or region. If within a year at least 10% are dead from a disaster then YES.
So you can start at any point in time and that is the group of people who count.
So if the people later flee they individually still count. If later refugees come to the city after the time we are checking, they wouldn't count for this interval.