Thursday 6 Dec 2012 6:16 p.m.
Whenever there's a disaster like the tornado that ripped through west Auckland today killing three people, one question always needs answering - was there a warning, and if not why not?
But tornadoes are not common in New Zealand and the current technology or science just isn't here yet that allows for their detection.
Meteorologists can tell us that if all the ingredients, such as severe thunderstorms, are present tornadoes are possible. But the prior detection of an actual tornado can't yet be done.
Radars and lightning detectors can track and identify bands of severe thunderstorms where tornadoes come from, but the flashpoint from thunderstorms to tornadoes is so rapid and variable that this level of detail or detection is not yet possible.
New Zealand tornadoes aren't like the ones in the United States which form from multiple super-celled thunderstorms within a definite, recurring area. Ours are much more unpredictable and volatile.
This afternoon a cold front or parcel of cold air connected with all the muggy warm air that's been feeding over us for the last couple of days.
The cold air came in like a wedge underneath it and thrust all the warm air upwards.
That's what created the band of thunderstorm clouds, and that's where you get extreme, violent upthrusts and downward motions of air.
And when those channels of air makes contact with ground, tornadoes form.