Wed. Jan 26th, 2022

It has been a week of wild weather in eastern Queensland with violent storms, record-breaking giant hail and three tornadoes.

On Friday morning, a tornado briefly touched near Brisbane Airport as a supercell storm moved, causing some damage and delaying and diverting flights.

The cell also brought hail and intense rainfall – with 101 millimeters recorded at the baggage point in one hour.

It comes after two other tornadoes were observed Monday as part of severe thunderstorms – one at Pittsworth in the Darling Downs and another at Bracewell near Gladstone.

How rare is it?

It was rare to see signs of three tornadoes in a week in Queensland, especially near populated areas, the Bureau of Meteorology (BOM) said.

However, this does not necessarily mean that they occur more frequently, as many occur in remote areas and therefore are not reported.

BOM senior predictor Kimba Wong said it was not “entirely uncommon for tornadoes to occur with such really intense storms”.

Cloud formation resembling a tornado at Bracewell near Gladstone
Cloud formation resembling a tornado near Bracewell near Gladstone in central Queensland on October 18, 2021.(Delivered by: Heather Cuzens)

What causes them?

Tornadoes usually occur with heavy thunderstorms, mostly supercells.

But they also need some other important ingredients to form.

“In general, tornadoes are driven by very strong winds, but also wind-cutting — so you need that kind of low-level rotation often associated with thunderstorms when they occur,” Wong said.

“You also need a lot of instability in the atmosphere to get the rotation going and the really, really strong upgrades that lead to that kind of tornado occurrence.”

The offset wind shift mentioned in the BOM is defined as a change in wind direction and / or velocity over a vertical or horizontal distance, which encourages the atmosphere to rotate.

A tornado passes near the northern city of Queensland, Atherton
A tornado passes near the northern city of Queensland in the city of Atherton in February 2010.(Robert Strachan: User submitted)

Can they be dangerous?

They certainly can be.

Wong said the three Queensland experiences this week had little impact due to their “transient nature”.

“Of course, if you get some stronger ones coming through, they can cause very significant damage, so it doesn’t have to be taken lightly,” Wong said.

A tornado descended on Bucca, near Bundaberg in southern Queensland, in 1992.
A tornado falling on Bucca, near Bundaberg, in 1992.(Supplied: Bureau of Meteorology)

Will we see more this year?

It can not be ruled out.

There is no defined tornado season in Australia, but they occur more commonly in late spring to early summer.

“This spring has already shown that it has got off to a good start in terms of storm activity throughout Queensland and into New South Wales and elsewhere in Australia as well, so it probably cannot be ruled out,” Wong said.

“It’s very difficult to pinpoint exactly where these tornadoes may occur.

“Even when severe thunderstorms occur, if a tornado occurs in connection with these storms, they can be very transient and short-lived in nature and difficult to detect unless we see these reports come through.”

Afternoon storm clouds swirl over Brisbane on March 2, 2021
The afternoon storm clouds are swirling across Brisbane in March this year.(Delivered)

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