THe problem in the US is not about knowing or not, it is before that. How high is the consciousness level ? The preparation level ? How much do people in charge care about the issue ? etc.
Evacuation is on an issue when the level of consiousness and readiness is enough.
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I think you're truly on to something here.
Across the United States, there are people living in areas that, due to a high probability of storm, earthquake, flood and other sorts of recurring, devastation events, can be considered 'be prepared for evacuation' zones.
But there's a reluctance -- both on the part of government, which is increasingly inept at performing the fundamental tasks a complex society demands (a result, in no small way, of deliberate de-skilling and de-funding), and also on the part of ordinary citizens (and let's focus on those with sufficient means to choose where and when and how) -- to keep ever present in mind the possibility that the lovely spot you've decided to call home rests in the path of predictable, and extraordinarily destructive, natural forces.
Perhaps not always predictable regarding time, date and so on (i.e. a major earthquake in S. Calif.) but surely predictable inasmuch as knowledgeable people have provided high quality warnings of the consequences of almost inevitable planetary processes being unleashed where you happen to be.
This reluctance, in addition to issues of class, race, poorly planned development patterns and other ingredients of the often very nasty brew we call America, prevents all sorts of folks from developing a "this shit definitely will happen" mindset that would build a robust evacuation and recovery organizational structure.
In a way, there's an odd logic at work. To move to destruction-prone places you must believe that what you've been told -- the worst case scenarios -- are really just scary stories; not very likely to happen. Otherwise, why would you invest so much time, energy and capital?
Better to think that the bad things won't happen, that your house will be fine, your lifestyle spared, your loved ones unharmed.
Planning for evacuation, practicing evacuation, discussing the need to leave it all behind would be an admission that the situation is unstable, the future uncertain; that immense and uncaring forces can sweep you away in a moment as if you were as weightless as a dream.
Not a pleasant thought for most of us. So we don't plan...in any serious way...and things unravel. The report, predicting catastrophe, sits on our desk, unread.
.d.