Readers of Nassim Nicholas Taleb's influential book The Black Swan (2007) might at least have taken such surprises in their stride. Taleb's thesis is that unpredictable events are a much more regular and important part of life than most of us believe.
But we are only too ready to try to rationalise the unpredictable in retrospect: "Our minds are wonderful explanation machines, capable of making sense out of almost anything, capable of mounting explanations for all manner of phenomena, and generally incapable of accepting the idea of unpredictability."
He called the phenomenon - "the highly improbable consequential event" - a Black Swan after the way the discovery of the first black swan in Australia overturned instantly and forever the existing Old World orthodoxy that all swans are white.
As writers of 'the first draft of history', journalists' reactions to Black Swans are similar to those of historians. As Taleb puts it: "These kinds of discontinuities in the chronology of events did not make the historian's profession too easy: the studious examination of the past in the greatest of detail does not teach you much about the mind of History: it only gives you the illusion of understanding it."
The volcano story is a classic example of what Taleb is talking about: a massive event coming from nowhere with huge and diverse consequences.
Looking backwards in covering the story is a fruitless journalistic task: there's nobody to blame and no apparent trail of causes, human or scientific, to explain it. But, if Taleb is right, explanations - spurious or otherwise - will eventually emerge. (Look at the financial crisis: with all the explanations since assembled, it is now hard to remember nobody saw it coming.)
So what about journalistic efforts to capture other aspects of the volcano story? There's been much detail about what happens when jet engines are coated with dust; what it's like to be stuck in an airport; and whether a gap in the dust is in prospect.
More lateral or forward-looking reports took a while to emerge last week. On Friday's Any Questions on BBC Radio 4, someone asked what the most important consequences of the volcano would be, but the panellists mostly just took that as a chance to support the decision to close airports and to offer their condolences to those who are affected. Radio 4's PM had an interesting piece with the owner of a fruit-importing business who talked about the dire effects on African farmers.
The most imaginative response I heard came from Alain de Botton on Saturday's Today programme: he read a delightful essay in which he had future generations questioning our contemporaries about the bizarre world of air travel which was by then just a piece of history.
Any Black Swan should be a great opportunity for journalists - a chance to lead public discussion about a wholly new situation. The possibilities are endless: in this case, for instance, what does it mean for national defence, language schools, high-tech exporters, the film industry, the insurance business, the price of oil, climate change, airport expansion protesters, passenger ships? What about the thousands of individual human stories that must be playing out already - missed weddings, funerals, holidays, job interviews, performances. And what good things are emerging from the unexpected situations people have found themselves in?
Perhaps there has been a hesitation to go down these routes because of a possibility that the story could be over by tomorrow. But, even if it is, the uncertainty about a recurrence will surely remain, and itself have consequences. This is a Black Swan that journalists can afford to embrace wholeheartedly.
But what about Nick Clegg? The journalistic machine is more ready to explore a political Black Swan. In fact, election coverage demands unpredictability for fear of simply providing unmediated airtime for the parties' messages. But the dilemma with this kind of unpredictability is whether to embrace with enthusiasm, like the Sunday Times, and risk over-hyping it, or more cautiously, and risk 'missing the story'?
In making that kind of judgment, journalists are face to face with Taleb's realisation: that it will only be in years to come that apparently obvious signs will be pulled from the maelstrom of current events and be shown to point inexorably towards a conclusion that we, in our present ignorance of how things will unfold, are unable to predict. Is the Clegg story the start of something big, or just a little bit of nothing much? Because if we knew we'd treat it accordingly.
No wonder so many journalistic enterprises admit defeat with the tired but honest sign off, 'only time will tell'.
