Disasters occur when disease spreads so far that it canít be contained, when the electromagnetic fields of the brain lose order and cause a seizure, when clouds convert from fantastic puffy shapes to towering thunderheads that emit tornadoes across the plains, and when economies switch from boom to bust.
The transition from tranquility to disaster is also like water turning to steam.
Have you ever put a cup of water in a microwave for a few minutes? Plenty of time that it should have boiled, but didnít? Then you reach in to remove the cup and, at the slightest jostle, the water bursts into a boil. What has happened is that the water reached a temperature above the boiling point without making the transition to steam: it superheated to a meta-stable fluid state and the tiniest perturbation to the system caused a dramatic change.
Well, we have pretty good understanding of how the system works---but the time evolution is very sensitive to the initial conditions, in the sense that two systems, starting from arbitrarily close initial states, can evolve all over the available phase space. Since we can't know the initial conditions with infinite accuracy, we can't predict the outcome either. This is the nature of chaotic systems---chaos has a quite precise mathematical meaning.
Finding consistent transition points have been the bane of science for a long time.
Simple systems can be characterised with measurements and controlled tests.
Our true understanding of the atmospheric system is very incomplete. There is a big gap still between what we know, what we think we know and how the system really works.
We are getting closer, but we are far from consistent prediction.