Final answer:
The pivotal factor that makes an event a disaster is that it poses a threat to life, property, and the environment.
Step-by-step explanation:
The pivotal factor that makes an event a disaster is that it poses a threat to life, property, and the environment. Disasters are characterized by their potential to cause significant harm and damage, including injury or death, destruction of homes or infrastructure, and negative impacts on the natural environment. For example, natural disasters like hurricanes, earthquakes, and floods can cause widespread devastation and loss.