I have followed the discussion with interest. I am genuinely puzzled as to why fire bunkers, shelters, call 'em what you will, are not employed more widely in the bush/suburban interface.

Susan, you are in Australia, as I am? Well, you know the scale of the disaster and the cumulative factors that triggered the firestorms.

Four years of drought, a huge fuel load, drying winds all conspired to produce the Perfect Firestorm.

Cost as at five days after Black Saturday:

181 lives lost. Many others seriously burned.

1100 homes destroyed.

200,000 hectares burnt, uncounted numbers of stock lost and farms destroyed.

There will be a Royal Commission and Coroners Courts, but there's no doubt this mega-fire was way beyond any human agency to combat. There is no sight more pitiful than someone standing on their roof [ usually in shorts and T shirt ] spraying water around with a half inch hose.

Which brings me back to the bunker/shelter. One or two canny people had shelters, and they survived. These weren't even professionally designed. But they gave that vital protection, just for that 15 or so minutes that it take for a firefront to pass.

There's a guy who lives a few miles from me [south of Sydney ] who has built two reinforced concrete dome shelters on his rural property. He's a Rural Fire Service veteran and says he would obviously trust his shelters with his life.

Simple, proved fire protection, which gives him the option to fight the ember attack against his home until the last minute before retreating into shelter.