such as the death of a pet, the separation or divorce of parents, or having trouble in relationships with peers
a future event
If the probability of an event is zero then that event cannot happen
Probability is the measure of how likely an event is. ... The probability of event A is the number of ways event A can occur divided by the total number of possible.
Species become extinct all the time. So the probability that one species or another will become extinct in the near future is one (meaning a certainty). But if you are asking whether a catastrophic event -- such as a huge asteroid striking the Earth and causing cataclysmic devastation -- will lead to mass extinction of all Earth's species, well, that's another matter altogether. According to NASA, the probability that the Earth will be struck by an undiscovered near-Earth object (NEO) that is bigger than one kilometer in diameter is one in 100,000 per year. The chances are much greater -- one in just 100 -- for objects the size of the one believed to have devastated a region of Siberia in 1908. (See provided link to the Tunguska event.) I am assuming that a 1-km asteroid would wreak sufficient havoc to destroy most, if not all, life on the planet.
Strong stressor that occurs suddenly, affecting many people at once
This cataclysmic event is called eruption.
an event
The apocalypse will be a cataclysmic event (if the apocalypse is real)
an event
The point of impact or cataclysmic event.
stressor
a stressor.
STRESSOR
STRESSOR
Stressor
stressor