The answer is "rapid-onset disasters".
We can categorize disasters as rapid-onset disasters and slow-onset disasters. The basic factor here is said to be the idea of the hazard concerned. Risks that emerge abruptly, or whose event can't be anticipated far ahead of time, trigger rapid-onset disasters. Earth quakes, violent winds and different windstorms, avalanches and torrential slides, out of control fires, surges and volcanic ejections are generally classified as rapid-onset disasters.
