No one could have predicted the scale of the bushfires that spread across NSW and exceeded even the worst case scenarios, the man who led the state's fire response says.
Former NSW Rural Fire Service commissioner Shane Fitzsimmons has described the 2019-20 bushfire season as extraordinary and unprecedented in terms of weather, fire behaviour and the widespread damage, destruction and tragedy.
"We saw an area burnt across NSW like we haven't seen before particularly across the forested areas," Mr Fitzsimmons told the natural disasters royal commission on Wednesday.
"We saw a protracted nature of the fire season without any meaningful interruption from weather."
Mr Fitzsimmons, who now heads the state's lead disaster management agency Resilience NSW, said traditionally there would be some reprieve in the weather, but that did not happen last season.
He noted the outlook for the 2019-20 season had been almost identical to that for 2018-19 in terms of where above-normal fire activity was expected, but the situation was compounded by the drought drying the landscape and vegetation.
"Obviously the indications were for above normal, but no one had the capacity to forecast and predict the extent and the scale to which weather and fire behaviour played out with a stretching of fire literally from the Queensland border all the way through to the Victorian border along the Great Dividing Range."
Mr Fitzsimmons said the fire behaviour and fire spread on a number of occasions well and truly exceeded the worst case scenario under the latest available modelling.
"We saw fire behaviour at two, three or four in the morning the likes of which you might normally expect at two, three or four in the afternoon where traditional conditions are at their worst."
The bushfires in NSW led to 26 deaths and affected 50 local government areas, burnt 5.5 million hectares, destroyed 2476 houses, 284 facilities and 5559 outbuildings.
There were close to 200,000 firefighting shifts used to battle 11,000 to 12,000 fires that started in July, and 6500 interstate and international personnel came to the state's aid.
ACT Emergency Services Agency Commissioner Georgeina Whelan said the effects of the territory's latest bushfires were significant, particularly given people's memories of the devastating 2003 fires.
"We had a community that was on a heightened level of alert, that had significant concerns as a consequence of their experience in 2003 and had very high expectations of a quality response from our emergency services," Ms Whelan said.
The ACT was covered in choking smoke from the NSW fires for weeks while its emergency services dealt with multiple hazards concurrently including its largest hail storm, as well as helping its neighbours.
"Suffice to say, it was probably the most challenging of times for the entirety of our agency, our emergency services, paid and volunteer staff and certainly the community," Ms Whelan said.
The Orroral Valley fire in January burnt almost 88,000 hectares in the ACT.
Four people died in the 2003 bushfires that burnt about 165,000 hectares, or more than 70 per cent of land in the ACT.
Australian Associated Press