Auckland tornado impossible to predict - expert

A fire rescue crew at a building site near Walingford Way in Hobsonville.
A fire rescue crew at a building site near Walingford Way in Hobsonville.
Fire rescue crew work to free people trapped by a concrete slab on a building site near Walingford Way in Hobsonville.
Fire rescue crew work to free people trapped by a concrete slab on a building site near Walingford Way in Hobsonville.
Emergency services work to free people trapped by a concrete slab on a building site in Hobsonville.
Emergency services work to free people trapped by a concrete slab on a building site in Hobsonville.
Damage in Hobsonville.
Damage in Hobsonville.
Road flooding in Auckland.
Road flooding in Auckland.
The remains of a double car garage in Whenuapai.
The remains of a double car garage in Whenuapai.
Destruction on Wallingford Way in Hobsonville.
Destruction on Wallingford Way in Hobsonville.
Auckland city around noon today, from www.sitecam.co.nz/auckland_webcam/.
Auckland city around noon today, from www.sitecam.co.nz/auckland_webcam/.
An emergency worker in Hobsonville.
An emergency worker in Hobsonville.
A trampoline flung into a house in Hobsonville.
A trampoline flung into a house in Hobsonville.
Destruction on Wallingford Way in Hobsonville.
Destruction on Wallingford Way in Hobsonville.
Destruction in Hobsonville.
Destruction in Hobsonville.
Emergency services work amongst destruction on Wallingford Way in Hobsonville.
Emergency services work amongst destruction on Wallingford Way in Hobsonville.
Emergency services work amongst destruction on Wallingford Way in Hobsonville.
Emergency services work amongst destruction on Wallingford Way in Hobsonville.
Emergency services arrive in Hobsonville.
Emergency services arrive in Hobsonville.
Inner Auckland is hit with rain.
Inner Auckland is hit with rain.
Damage to housing in Hobsonville.
Damage to housing in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Storm damage obstructs a road.
Storm damage obstructs a road.
The aftermath of the tornado in Hobsonville.
The aftermath of the tornado in Hobsonville.
Storm damage in Hobsonville.
Storm damage in Hobsonville.
Sharon White with her three year old son, and their overturned trampoline.
Sharon White with her three year old son, and their overturned trampoline.
The storm rages in Hobsonville.
The storm rages in Hobsonville.
Flooding begins in Glen Eden.
Flooding begins in Glen Eden.
Heavy rain at the Dotcom mansion.
Heavy rain at the Dotcom mansion.
The view from a city centre office, taken by a Twitter user.
The view from a city centre office, taken by a Twitter user.
Dark clouds gather over Takapuna.
Dark clouds gather over Takapuna.
Guttering fails to cope with the heavy rain in Auckland.
Guttering fails to cope with the heavy rain in Auckland.
Heavy rain causes flash flooding just after midday in Auckland.
Heavy rain causes flash flooding just after midday in Auckland.
A motorist captured this picture on Auckland's North Shore as grey clouds hit the city.
A motorist captured this picture on Auckland's North Shore as grey clouds hit the city.

Northwest Auckland has been hit by three deadly tornados in 20 years but it would have been impossible to predict the tornado that claimed the lives of three men on Thursday, an expert says.

MetService meteorologist Daniel Corbett said the mixture of temperatures coming from the land and the sea, combined with wind speed, made it an ideal area for tornados to form.

 

Corbett said meteorologists could not predict tornados in the area. A radar used by staff was unable to spot the smaller kind of twister likely to strike in New Zealand.

"Our tornados are only tens of metres wide," he said.

"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 tornados."

Twisters in the US occur in the warm season but tornados here were largely a colder weather phenomenon, he said.

"They're small, short-lived and dissipate within minutes."

Corbett said the Hobsonville tornado wasn't solely responsible for the destruction that caused about $13 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 said the incident was a reminder to people to pay close attention to weather warnings about strong winds and heavy rain.

"Those are the days you want to plan to be at home or work and not be going out to the park.

"If you're in a tornado at home get into a closet or cupboard or go to the middle of your house keeping well away from glass. Otherwise get into your car if you've got nothing else."

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

Auckland Now