Hundreds of thousands of people face a growing bushfire calamity, with the entire Blue Mountains area as well as Penrith and Richmond in danger of burning over the next few days.
Premier Barry O'Farrell on Sunday took the extraordinary step of declaring a state of emergency across NSW for the next 30 days, which will give special powers to all emergency services to deal with what could be a catastrophe.
Mass forced evacuations affecting tens of thousands of people are possible as hotter and drier than expected conditions combine with huge fire fronts already burning. Live details of active fires - click on the icons for more information. Source: NSW Rural Fire Service.
''This is not out of the realms of possibility,'' NSW Rural Fire Services Commissioner Shane Fitzsimmons said. ''We are expecting the potential for the series of these fires to come together, to extend right down Bells Line of Road. Advertisement
''They have the very real potential to go right out to the eastern end of the Hawkesbury, right down into the north-west area of Sydney including Richmond.
''That's what we are talking about, the run from Bilpin right through to Richmond.
''We are also talking about the fires coming down the northern areas of the Great Western Highway, everywhere from Blackheath to Katoomba, Leura and all the townships all the way along to places like Springwood and Winmalee.
''That's the magnitude. I sincerely hope it's not realised and we end up somewhere in between, but what we can't ignore is the probability, based on the weather forecast and based on the current fire behaviour that we've experienced and which we are continuing to experience across these fire grounds.''
The weather would be at its worst on Wednesday, with the forecast for high temperatures, low humidity and high winds being assessed as much worse than predicted last week.
''We are not in a catastrophic [weather] ratings scale [but] we are talking about fire danger ratings that will be in the severe category - and you overlay that with the fires that are already burning and it's a whole new ball game,'' Mr Fitzsimmons said.
The worst fire disaster in NSW for at least 45 years could lead to evacuations from high-population centres such as Katoomba and Leura.