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Cyclone season much busier than usual for NZ

It’s been a long time since New Zealand saw so many tropical cyclones in our waters – but 2011 will go down as one of our busiest cyclone seasons ever predicts

In less than a month four tropical cyclones have entered New Zealand waters with all of them having some type of severe weather impact on the country. 

Vania was the first, it weakened significantly before landfall but merged with Cyclone Zelia, which kept Category 3 strength until it neared New Zealand.  The two systems combined to bring torrential rain and flooding to the West Coast and a spell of incredibly humid weather over the upper North Island.

Then we had Cyclone Wilma.  Philip Duncan revealed in his Herald on Sunday column this past weekend that Tropical Cyclone Wilma was the first ever tropical storm in recorded history to retain it’s “tropical cyclone” status when it reached New Zealand.  It was a category 2 cyclone as it brushed past Northland then rapidly fell apart.

Wilma caused significant flooding and flash flooding and has left millions of dollars of damage to roads and properties in the upper North Island, including demolishing an entire house on Waiheke Island.

And on Monday of this week another cyclone not also surprised forecasters but also was another one to challenge the record books, becoming a tropical cyclone within MetService’s area of responsibility (in other words, south of the Fiji Meteorological Service’s area of responsibility).  Tropical cyclone rarely form this far south due to cooler sea surface temperatures.

Zaka is only a very minor system and isn’t expected to have any serious impact on New Zealand as it quickly weakens in the coming 24 hours and passes east of East Cape as a “normal” small low pressure system.

According to NIWA there have been six named storms so far this season and they predict another 6 more named storms before the cyclone season finishes in April.

While New Zealand is at an elevated risk of a cyclone this year NIWA normally only expects one cyclone to come near the country during the cyclone season.

We’re now only at the half way mark and we’ve had four, proving that La NIna is having a significant affect on our weather pattern this summer.

Image / JTWC predicting where the remnants of Zaka will pass.  The small low will be fairly insignificant when it passes by to our easy on Wednesday but will bring in some rain or showers and rougher seas around East Cape



Ding.Ding.Slap -_- on 8/02/2011 6:18am

so umm everyone’s been Talkin aBOUT a cyclone in the South….. Im so pissed so wat do i do??? What is tHere 2 do =[
Problly Just Hang on tight Right!!

roy on 7/02/2011 11:04pm

Hey there if Cyclone Wilma was the first ever tropical storm in recorded history to retain it’s “tropical cyclone” status.

What about cyclone bola on th 7 mar 1988

WW Forecast Team on 7/02/2011 11:29pm

Hi Roy – most of the cyclones that come out of the tropics retain their name – eg Bola, Fergus, Drena etc, simply because once they have been named it makes sense to continue calling them that. 

Bola was still a storm with severe winds and torrential rain – but technically it’s internal structure had completely changed (ie, if you looked at a satellite map it no longer looked like a cyclone with an eye).  When a tropical cyclone is downgraded it’s because it no longer has a warm core.  That transition happened to Bola – so while still aggressive and severe it was technically no longer a "tropical cyclone" and was in fact extra-tropical. 

Hope that makes sense!?

Philip Duncan

Nikki on 7/02/2011 10:13pm

Is it due to climate global warming and warmer waters the reason why we are seeing so many more cyclones close to New Zealand?
Do you think NZ will be affected with a big one this season?

WW Forecast Team on 7/02/2011 10:29pm

Hi Nikki – that’s a great question.  I think it’s hard to put one season into the "climate change" box but in saying that it may well be part of the collective change in weather due to climate change.  We need to wait and see if it repeats itself over and over.  One off events (including strong La Ninas) aren’t proof of climate change forecasts – neither are big tropical storms like Yasi and Katrina.  However if we’re seeing more and more of these large scale storms that I’m certain that is proof.  The planet is definitely warming – we’ll leave whether that;s due to mankind or not for another debate – so certainly with a warmer planet we will have more rain events, cyclones and droughts.  But our time scale is very short and we need more time to see if this is happening.  In the meantime Climate Change scientists are saying we can’t really wait – and that they believe they have the proof that this is happening now.  (Scientists will see and understand things well before the general public will).

We also have much better news coverage of these storms, so it may feel like there are more extreme events happening – but in reality there was no one source for our cyclone season until started.

I don’t know if we’ll see a big cyclone – bigger or more damaging than Wilma was.  We’re certainly at an increased risk but the odds should be stacked against us – especially considering we’ve had 4 already!


Philip Duncan

weather-nut on 7/02/2011 8:06pm

I think TC Zaka was around 24.2¬∞S when named by Fiji Met early yesterday morning, whereas NZ’s area of responsibility begins south of 25.0¬∞S. Remarkably though, Zaka does appear to have formed outside of the tropics, i.e. south of 23.4¬∞S.

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