Can I suggest that the quote by Greg Mullins should not be taken absolutely literally ?
He was saying that areas that had slow burns only a few weeks back still burnt fiercely when the bushfires hit.
So a slow burn reduces a fair amount of the fuel. But the trees are still standing. The branches and leaves are still intact. On the ground a fair bit of undergrowth has been burnt, half burnt. There will be stuff that has charred rather than being turned into fine ash.
Anyway that is my experience when I was doing fuel reduction in the 80s/90s
The intention of the fuel reduction is to not allow a fire to reach extreme temperatures that will destroy rather than singe mature trees.
The situation Greg Mullins was highlighting was the new reality of 2020 fires. Overall air temperatures were hotter than ever. The long drought had dried the ground and trees to levels not previously seen. Higher overnight temperatures mean fires don't even die down at night as they once had. As a consequence fires were now becoming so intense they were literally creating their own
fire storms. These fire storms have happened (rarely) in the past but occurred much more in the 2019/20 fires.
It is these realities that caused Greg Mullins to highlight the critical role global heating has in intensifying fires to levels that are now unfightable. It is why we now have a catastrophic bushfire warning level at the top of the list. It is why tackling CC is a critical focus for fire management. Attempting to divert attention to just fuel reduction processes is inadequate.
Firestorms have been reported in several countries where wildfire is prevalent, including the U.S., Canada and Russia. But they appear to be becoming more common and more severe as conditions become hotter and drier as a result of human-driven climate change.
Australia has seen a dramatic uptick in the number of firestorms since 2001. According to a piece in Fire Australia, a joint publication from the Bushfire and Natural Hazards Cooperative Research Centre, Australasian Fire and Emergency Service Authorities Council (AFAC) and the Fire Protection Association Australia, there were just two minor pyroCbs reported between 1978 and 2001. The following 15 years (2001 to November 2016) saw 56.
The scale and intensity of Australia's wildfires are triggering firestorms and firenadoes. Here's why.