The state coroner has confirmed that a bushfire that destroyed homes in Mt Wilson, Mt Tomah, Berambing and Bilpin in December 2019 was caused after a planned RFS backburn jumped Mt Wilson Road, sparking spot fires which quickly spread.
But the coroner declined to make recommendations sought by a number of affected residents, including about the appropriateness of advice and warnings. She said those issues were outside the scope of her inquiry.
Teresa O'Sullivan handed down her findings on March 27 into the Black Summer bushfires, including into the deaths of 25 people across the state, seven of them fire-fighters.
She made 28 recommendations to the RFS commissioner, the NSW Police commissioner and to the CEO of Essential Energy.
In relation to the Grose Valley fire which burnt 22 homes and 30 out-buildings in the northern stretch of the Blue Mountains local government area, she found that it was started by the strategic backburn at Mt Wilson.
It was meant to halt the progress of the massive Gospers Mountains fire, the so-called "mega blaze" which burnt 512,600 hectares over 15 weeks and was the largest single forest fire in Australian recorded history.
Ms O'Sullivan said the backburn was lit on December 14 when winds and humidity were predicted to be as good as conditions could get during that extremely dry and dangerous summer.
But the humidity levels dropped and the wind direction changed at lunchtime, the easterly turning south-westerly which pushed the embers across Mt Wilson Rd and eventually into the Grose Valley.
Residents whose properties burnt the next day had told the inquiry the emergency warnings they were given on December 14 and 15 were not timely or appropriate and gave them little indication of the level of threat they faced.
Ms O'Sullivan noted that some communities affected, including Mt Wilson, had only one road in and out, "leaving them with little option but to shelter where they could and brace for impact. Even those who were on notice of the oncoming fire were not prepared for its relentless ferocity and speed."
But she made a recommendation that the RFS develop training for public liaison officers addressing the "significance of early warning to communities with limited access to reliable communication systems".
She also recommended to both the RFS and NSW Police commissioners that if it was suspected that a bushfire had started because of a backburn, police could ask for modelling from the RFS to consider what might have happened if the backburn hadn't taken place.
The residents had also asked that the NSW Government formally apologise to residents, fire-fighters and communities impacted by escaped backburns and that it set up a compensation scheme for those affected by the Mt Wilson backburn and other backburns.
But Ms O'Sullivan said it wasn't appropriate for her to make such recommendations as the NSW government had not been represented at the inquiry by a capable department and had not been asked to comment on the appropriateness or practicality of any such recommendations.
