'Mini tornado' preceded Tasmania jumping castle tragedy

A jumping castle tragedy that killed six primary school children in Tasmania was preceded by a powerful and concentrated "mini tornado" wind gust, a pre-inquest hearing has been told.

Families of Zane Mellor, Peter Dodt, Jalailah Janyne-Marie Jones, Addison Stewart, Jye Sheehan and Chace Harrison were present at Devonport Magistrates Court on Tuesday.

The Hillcrest Primary School grade five and six students died following the incident on December 16 last year during end-of-year celebrations on the final day of term.

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The court was told the inquest could not realistically begin within the next six months because of its complexity and the need to inspect further evidence.

Counsel assisting the coroner, Leigh Mackey, said the gust that lifted the castle and several inflatable Zorb balls into the air could be described as a mini tornado or wind devil.

"It appears to have been powerful and concentrated. The castle appears to have been lifted by the wind to a great height," she said.

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Zane, Peter, Jalailah, Jye and Chace fell from the castle, as did two of their schoolmates who survived.

Addison was standing nearby when she was struck by an object, potentially a blower attached the castle.

Three Zorb balls occupied by three students were also lifted into the air.

The children suffered serious injuries but survived.

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Mackey said WorkSafe Tasmania was seeking further expert opinion on tethering as part of ongoing investigations.

The court was told there were 39 students on the oval at the time of the incident, and grade five and six children were taking part in activities during a 55-minute window.

The inflatable castle and Zorb balls had been provided by TasZorb.

The students were being supervised by three TasZorb staff and teachers.

Coroner Olivia McTaggart warned families would hear confronting evidence when the inquest began.

She said a further case management conference was required beforehand to organise evidence and provide information to lawyers and families.

McTaggart expressed her sympathies to the families and loved ones of the victims, and noted the efforts of school staff and first responders who helped in the aftermath.

"It is an event that has touched and saddened the whole Devonport community," she said.