I am very fond of Australia & always have had a weak spot for it. Its very amazing to me that today's technology cannot produce a cost effective shelter safe from fire for this area. Sort of like storm shelters used in the USA to hide safely from a tornado; or bomb shelters in the middle east. Air & temperatures extremes would be the larger problems BUT the time frame would only have to be for a short period. Is concrete cost effective there? Air filters & fans could take care of the air problem. Alot of schools now are built with area storm shelters; maybe area fire shelters in towns & the rooms still can be used for a general use purpose. Got to start somewhere as this is way way to costly to avoid a prevention drive!
Tornado's use to kill many in the USA until an effort was directed toward prevention and now to loose even one to a tornado is not very common.
Lets hope the fortunes for, our friends, the Aussies also can turn a diaster through technology into a NON-REPEAT.
We are very deeply sorry for ALL your losses!