Day by day this week the world has watched a mounting horror in the United States. The hurricane that hit the Mississippi delta on Tuesday night, New Zealand time, was not the normal passing calamity of gales and flying debris. Hurricane Katrina struck the Gulf coast with less force than it threatened as the vast wind system moved toward the shore, but it breached the levees that protect a city built largely below sea level and brought the flood so long expected for New Orleans.
Long expected but somehow not anticipated. The levees which had long been predicted to fail could have been heightened, but it did not happen. Civil defence and rescue services might have been of a standard that did not leave people stranded on roof tops, but they did. Graveyards might have been moved because it was known floods would bring corpses to the surface, and they did.
The sports stadium where people were encouraged to take refuge lost electricity, fresh water, part of its roof and was itself flooded. The 23,000 who huddled there are now being bussed 550 kilometres to Houston. Then there is the looting. It is less important of itself than for what it says about the precautions, or lack of them, for the maintenance of civil order.
How could this happen, many wonder, in the world's richest and most advanced country? How is it that, even if sufficient precautions were not taken, the industrial and technological resources of the United States could not swiftly deal with the inundation? And, as often, when misfortune strikes the US, the social inequalities within it are starkly exposed.
Most of the 80 per cent of New Orleans residents who managed to evacuate before the hurricane were white and well off. Most of those who stayed and lost loved ones are predominantly black or Hispanic.
A combination of contaminated water, poor sanitation and the threat of tropical diseases has now placed the city under a complete evacuation order. There is no telling when it will be fit for human habitation again. It might never entirely recover. It might be regarded as a historic oddity, built where no planner would ever put a city now, which was lucky to be spared the obvious natural disaster for as long as it was, but which has now met its fate. If that is the verdict for the old French settlement and famed jazz centre, the world will be poorer.
Typically, the hurricane had barely done its damage before it was being cited as yet another exhibit of climate change. Rising sea levels and temperatures, it was suggested, made the devastation worse. The number of recorded hurricanes has been higher than normal in nine of the past 11 years. But, as some meteorologists point out, the globe has known periods of frequent storms before.
If human action has made this flood worse than any previously in the region, it is probably the draining of coastal wetlands which would have helped absorb floods like this. The levees and dams built along the Mississippi have also made the area more vulnerable in the event of a breach. They have prevented the river replenishing its flood plain with silt, with the consequence that the city has been gradually sinking.
No part of the world is entirely immune from the effects of a disaster on this scale. The damage to oil production in the Gulf of Mexico is expected to be felt in the petrol prices, and the cost of damage to insurers will be passed into premiums the world over. If the disaster had struck a different part of the world, appeals for aid would have been made. America is expected to look after its own, which it will. But it might appreciate some gesture of sympathy. Even the most powerful turn out to be frail in the face of nature.