Terror twisters take toll

20:26, Dec 10 2012
Tornado aftermath
The scene at the Hobsonville Point Secondary School construction site where three men where killed.
Tornado aftermath
A police checkpoint at the Hobsonville cordon.
Tornado aftermath
A security guard at the cordon of a Hobsonville construction site.
Tornado aftermath
The early morning clean-up in Hobsonville.
Tornado aftermath
The early morning clean-up in Hobsonville.
Tornado aftermath
The Hobsonville construction site which bore the brunt of the tornado.
Tornado Auckland
Rescue crews recover the bodies of three men the day after they were killed in a tornado.
Tornado aftermath
Debbie Booty hid in a wardrobe at her house in Wallingford Way, Hobsonville, when the tornado hit.
Tornado aftermath
Desiree Morgan, left, with daughters Izzy and Grace, and Huia Midgely receive milk supplies from across the cordon.
John Key Hobsonville
John Key arrives in Hobsonville to survey the damage caused by the tornado.
Tornado Auckland
The wrecked frame of a truck that was crushed by a concrete slab during the Hobsonville tornado.
Tornado aftermath
Phil Goff, David Cunliffe and David Shearer survey the damage in Hobsonville.
Tornado aftermath
Red Cross workers Wallingford Way in Hobsonville.
Tornado aftermath
Emergency service personnel talk to residents hit by the tornado.
Tornado aftermath
Red Cross workers prepare to meet residents affected by the tornado.
Tornado aftermath
A resident in Carnegie Cres, Hobsonville, fixes a window smashed in the tornado.
Tornado aftermath
Investigators survey the construction site where three men died in the tornado.

The tornado that claimed the lives of three men in Hobsonville on Thursday could never have been predicted with current technology, experts say.

MetService meteorologist Daniel Corbett says the radar used by staff is unable to spot the smaller kind of twister likely to strike in New Zealand.

"Our tornadoes are only tens of metres wide," he says.

Auckland Tornado graphic
DEADLY TORNADOS: Lives lost and damaged done by tornadoes in northwest Auckland.

"In the United States they are half a mile wide and the radar can pick up the whole thunderstorm turning.

"Because of the localised nature of these events they are undetectable and we have to forecast the conditions that would be favourable for tornadoes."

Mr Corbett says twisters in the US occur in the warm season but tornadoes here are largely a colder weather phenomenon.

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"They're small, shortlived and dissipate within minutes."

Mr Corbett says the Hobsonville twister wasn't solely responsible for the destruction that caused around $11 million worth of damage - the straight line winds that went with it also played a part.

"At Whenuapai wind gusts of 110km were recorded and that alone can be very damaging."

He says the incident is a reminder to people to pay close attention to MetService warnings about strong winds and heavy rain.

The strip between Albany and Hobsonville has been hit by three deadly tornadoes in the past 20 years.

North Shore Times