20 Jun 2021

Tornadoes hit too fast to predict - meteorologist

8:19 am on 20 June 2021

Meteorologists say predicting tornadoes is difficult and New Zealand does not have the technology to do it.

Downed powerlines and damaged roofs after yesterday's tornado.

Downed powerlines and damaged roofs after yesterday's tornado. Photo: Ben Wilson

A tornado ripped through Papatoetoe and Wiri yesterday morning, damaging 1200 homes, 60 of which are uninhabitable. A worker at a container freight hub in Wiri died in the high winds and two others were injured.

MetService had issued a thunderstorm warning for the area but in response to questions about why it did not forecast a tornado it said it does not have a warning system like the United States does.

NIWA meteorologist Richard Turner said predicting such events were challenging.

"Our technology in terms of our numerical weather forecasts are getting better, but then there's the real practical challenge of putting out warnings when tornadoes are actually occurring.

"In New Zealand they're very short-lived so by the time you get them out often the event has passed."

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A lot of tornadoes go unreported in New Zealand because they are in remote areas, but yesterday's one hit an Auckland suburb. Photo: Shamsher Randhawa

He said such technology could be developed in time.

"I think there's possibilities that with better computers, faster processes and the ability to resolve more detail in thunderstorms that we might get better at identifying which ones might be potentially more able to produce a tornado and what what sort of intensity they would be.

"That's probably still a few years away, but that's probably where the science is taking us."

He said a lot of tornado activity went unreported because it happened in remote areas.

"So that's really quite difficult [when] you're wanting to develop forecasting techniques from numerical weather predictions or the like, you need to have really good data to backup your learning.

"The hope would be we might be able to have artificial intelligence or machine learning algorithms that could identify the signatures within a numerical weather forecast that that could identify the risk ... but in order to do that you need to have the data."

Clean-up continues today

Fire and Emergency New Zealand crews have spent the night helping some of the 1200 homes affected by wild weather.

Fire and Emergency shift manager Paul Radden said teams have been going around properties checking people are okay, looking for leaks and helping clear debris.

"Three crews and a command unit are assessing the damage, the result of the weather that's happened in the last 24 hours."

Raddens said staff will continue to assess the situation this morning.

Meanwhile, MetService forecaster Andrew James said a low pressure system sitting over the Tasman Sea sent more rain over Auckland overnight, but that skies are expected to clear today.

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