Was that really a mini tornado on the Brisbane River?

No, that wasn’t a “mini tornado” tearing along the Brisbane River on Friday afternoon – but it’s a sign of more severe weather predicted for coming months as the state heads further into peak storm season.

Thunderstorms rolled across south-east Queensland late yesterday, with high winds, rain and hail hitting parts of the CBD about 4pm.

The “mini tornado” that tore across the Brisbane River on Friday afternoon has been labelled a “gustnado” by the Bureau of Meteorology. Credit: Nine News

There were reports of three- to five-centimetre hailstones in Morningside and across the inner city, while places like Boonah and Flagstone recorded six- and seven-centimetre stones respectively.

“That size is really gigantic,” senior meteorologist Angus Hines said. “Five centimetres is the cut-off, or the threshold, for what we classify as giant hail.”

The storm, which developed south-west of Brisbane and moved in a north-easterly direction before crossing the CBD, brought a brief heavy downpour and strong winds, resulting in what appeared to be a “mini tornado” on the Brisbane River around Kangaroo Point.

“Its technical term is a gustnado, which is similar to a small tornado but is not formed in quite the same way,” said Hines, from the Bureau of Meteorology.

Some of the large hailstones that hit Brisbane during Friday’s afternoon storm.Credit: Catherine Strohfeldt

“When we get a fully-fledged tornado, we expect to see that rotation start within the thunderstorm cloud, then it reaches out and touches down on the ground.

“Whereas what we saw yesterday, there was certainly a rotating column, or vortex, of air, but it didn’t have the direct connection with the thunderstorm cloud itself.”

The gustnado caused damage along the riverfront, with reports of trees down and branches across paths around Kangaroo Point.

Queensland is more synonymous with cyclones, although tornadoes have been known to form.

“A full tornado does happen once in a while, and parts of south-east Queensland are one of the few areas of Australia where it is possible,” Hines said.

The storm season has arrived slightly earlier than last year’s, with a number of significant downpours in the eastern states in the past three to four weeks.

A repeat of last year’s extreme weather over the Christmas and New Year period is difficult to predict, but the bureau is warning Queenslanders to prepare as the region moves into the peak of summer storm season.

“Spring and early summer is the peak time of year for this kind of weather in Queensland, New South Wales and, at times, further south in parts of Victoria,” Hines said.

“Over the next month and [into December and January], we’re likely to see more days that bring the risk of severe storms – the risk of high and significant weather impacts like the dry hail and damaging or destructive winds. The possibility of water spouts and small tornadoes is there as well.”

Looking ahead for the weekend, there is a chance of a “non-severe thunderstorm” around the south-east and heavy rain in parts, with more significant storms and severe weather further north around the Wide Bay-Burnett region, including Hervey Bay and Bundaberg.

Clear and sunny skies are predicted for Sunday and Monday, ahead of another possible severe storm on Tuesday.

More from the Bureau:

• From footage supplied to the Bureau of Meteorology, there was most likely a weak gustnado over the Brisbane River on Friday November 1, 2024.   
• The severe thunderstorm which impacted parts of south-east Queensland including Brisbane on November 1 was a supercell thunderstorm, this type of severe thunderstorm has a core which rotates cyclonically (clockwise).
• A tornado associated with this system would be expected to have cyclonic rotation whereas the gustnado over the Brisbane River was observed to have anticyclonic (anticlockwise) rotation. 
• Gustnadoes are driven by the associated gust front of a thunderstorm.
• A gustnado is not connected to the cloud base of a thunderstorm, and is not driven by the storm rotation.
• Gustnadoes tend to be weaker than tornadoes and are usually brief, lasting up to a minute or so.  

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