Karl du Fresne: Over-egged weather warnings just deepen our scepticism

The Wahine at the entrance to Wellington Harbour, a month after it foundered. We were told there was a real risk the ...
John Selkirk

The Wahine at the entrance to Wellington Harbour, a month after it foundered. We were told there was a real risk the intensity of Cyclone Cook would match that of April 1968, when the Wahine was stricken.

OPINION: An expat friend emailed me from Brisbane last week. He had read about Cyclone Cook hitting New Zealand and wondered whether, after all the scary warnings, it had turned out to be a bit of an anti-climax.

I had to confirm that his impression was correct. Sure, trees were brought down, some houses were evacuated, farms were flooded and there were road closures, power outages and a few landslides.

The impact on those affected shouldn't be understated. But there was nothing like the mayhem that breathless weather forecasters had warned us to brace ourselves for.

MetService should be conducting a rigorous self-appraisal this week, because it greatly overplayed its hand. In doing so, it put its credibility at risk. Some of the official predictions came perilously close to scaremongering.

We were told there was a real risk the intensity of the storm would match that of April 1968, when the Wahine foundered at the entrance to Wellington Harbour with the loss of 51 lives. But the conditions then were dissimilar in one vital respect.

It's true that in 1968 a tropical cyclone, Giselle, passed down the country, just as happened with Cyclone Cook. The crucial difference was that it collided head-on over Cook Strait with a powerful front heading in the other direction.

It wasn't Giselle on its own that caused catastrophe, but the violent clash of two opposing weather systems. Meteorologists must know this, so why create the misleading impression that Cyclone Cook on its own was capable of replicating Wahine conditions? It was wrong and it was irresponsible.

This isn't to say MetService was wrong to issue warnings. Clearly it would have been negligent not to advise the public to be prepared for an extreme weather event. There would have been hell to pay if Cyclone Cook had arrived without prior notice.

What's at issue is the sensationalist tone of the warnings. One over-excited forecaster pronounced that it would be a "national event" – no ifs, buts or maybes – and said not many people would be spared.

In fact the impact turned out to be largely localised, and not necessarily in the places predicted. Some of the predicted consequences, such as damaging storm surges and coastal inundation, appear not to have eventuated – or if they did, had little impact.

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The Auckland Harbour Bridge stayed open and the Cook Strait ferries continued running, contradicting expert predictions.

What's also troubling is that the meteorologists showed no inclination to moderate their forecasts even when it became apparent that they might have over-egged the pudding.

When Cyclone Cook deviated from its expected path, one forecaster pronounced that Auckland had "very luckily" been spared, but that the worst was still to come. Well, we're still waiting.

The Central Plateau and Wairarapa were supposed to cop it, but neither region did. I live in the Wairarapa and all that happened was that we got a night of moderately heavy rain from an unusual direction.

Once the cyclone had passed over the country and drifted off to wherever it is that ex-cyclones go, MetService went into damage control mode. By that time it was getting some stick on social media; one joker posted a photo on Facebook showing a plastic chair overturned by the wind on someone's back lawn as an example of the devastation caused.

A MetService spokesman explained that tropical cyclones were "fickle beasts which are hard to pin down".

Fair enough; we can all accept that forecasting is an inexact science. But if cyclones are unpredictable, why so much certainty before the event?

In fact I wonder if the whole business of meteorology and forecasting is becoming a bit overheated, if you'll excuse the pun. Fears of global warming (real or otherwise), 24-hour weather channels, celebrity weather presenters and constant warnings of extreme climatic events all feed into this phenomenon. But violent weather events have always been with us.

What should concern MetService is that its credibility took a hit last week, not so much because of the accuracy of its forecasts but due to the hyped-up, anxiety-inducing tone of its warnings.

It added to a deepening public scepticism toward "experts". People take note when weather forecasters give them a bum steer, just as they take note when supposedly state-of-the-art, earthquake-proof buildings – designed by experts – have to be abandoned after a moderate shake while decades-old structures are undamaged.

People notice, too, that there's a striking absence of accountability for the harm done when experts get things wrong. But that's a subject for another day.

 - The Dominion Post

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