Emergency warnings issued for out-of-control fires

The Rural Fire Service says "very dangerous" fire-generated thunderstorms has formed in NSW, with conditions "erratic". 

Dramatic footage has emerged of homeowners’ desperate attempts to save their properties from ember fires today, with as many as 20 homes now feared destroyed.

Soaring temperatures  into the mid-40s and strong winds have made bushfires erratic and difficult to control.

“The peak day for NSW and the ACT is Saturday,” Bureau of Meteorology forecaster Andrea Peace earlier warned.

“It creates a really dangerous period for the fire grounds because it (the wind) rapidly changes the direction of the fires there.”

Fires are out of control across NSW, in Victoria and in Adelaide, where tragically a second person was confirmed dead today.

Authorities have warned main highways, including the Princes Highway and Hume Highway, may be closed and motorists will be asked to turn around if they try to enter dangerous areas. People have been told to delay any travel plans..

A 'mega-blaze' has taken hold in Lithgow, two hours west of Sydney, with flames moving just metres from homes.  Multiple homes are now destroyed and one resident is unaccounted for. 

There are seven fire warnings in place across NSW, with many residents warned it's too late to leave.

Many are choosing to stay and fight, hosing down their homes with water.

Four firefighters have been treated for heat exhaustion. 

"Today's been an awful day, and we've already seen  property impacted and lost," RFS Commissioner Shane Fitzsimmons said in a press conference.