Shoppers stunned by twister
Dust-laden twisters typical of barren deserts have started springing up in the bone-dry Waikato.
Stunned shopper Paula Munro captured video footage of a twister funnelling about 100 metres into the air west of Te Awa on Sunday afternoon.
The bright orange dust devil looked like it was heading straight for the carpark, stopping people dead in their tracks.
Another shopper, Amanda Harper, said she saw it at about 1.30pm. "It lasted five minutes but didn't look dangerous.
"It was a fascinating sight to see."
MetService spokesman Dan Corbett identified the phenomenon as a dust devil.
They were a common occurrence on the parched earth of Arizona where he lived for a time.
They occur during the hottest part of the afternoon as air rises from hot areas of ground.
"If you had an infrared camera you could see all the warm air rising," Mr Corbett said.
"Imagine a gust of wind or a seabreeze coming in that twists that thermal - that creates the dust devil."
Dust devils are short lived and can travel for a few hundred metres and rise a similar distance into the air but they never reach cloud level, Mr Corbett said.
Winds are strong enough to knock over garden furniture, he said, but houses and other structures are perfectly secure.
Dust devils, as per the name, also pick up fine particles from the ground as they move. As soon as the thermal loses energy the whole thing collapses.
Mr Corbett said it was symptom of recent high temperatures in the region and there was no respite in sight over the next week at least.
"We've got a big high that breaks down a little bit by the weekend allowing weather systems to creep in and we have a glancing blow from a subtropical low in eastern parts of North Island, perhaps the Bay Of Plenty and Gisborne."
Unfortunately, Waikato misses out.
"There's another low that may creep in over the weekend that could give some showers but even that is a smallish risk."
Mr Corbett said as we move into the first weeks of autumn there should be a decent dose of rain to ease the soil moisture deficits.
"One system won't solve all the problems. It'll probably take two or three but give it a couple of weeks and we'll start to see things moving again because we've been stuck.
"Fingers crossed," of course.
- Waikato Times