Canberra is in a state of alert amidst extreme bushfire danger that threatens to create disaster in the ACT if a fire were to break out.

Key points: The ACT is in a state of alert due to extreme fire conditions expected today

The ACT is in a state of alert due to extreme fire conditions expected today There are currently no bushfires burning in the territory

There are currently no bushfires burning in the territory Firefighters are concerned that any new ignitions will quickly become difficult to control

Shelves stocking bottled water have been stripped bare in some supermarkets and Canberrans are being urged to ensure their bushfire survival plans are ready to be actioned in the event of a fire.



Here's why today is being taken so seriously, and what you need to know.



Are we in danger of fires?



As of Saturday evening, there are no fires burning in the ACT.

The territory has been heavily affected by smoke from fires burning in the surrounding region for nearly a month, but the blazes are out of range of the ACT and modelling conducted by the Emergency Services Agency (ESA) suggests those fires are very unlikely to reach the territory this weekend.



But authorities are concerned that new fires started by dry lightning strikes or arson could quickly become difficult to control.

Hot, dry conditions with winds from the northwest are headed for the territory, and predictions of 42C highs have been surpassed, with the ACT's hottest ever temperature, 44.0C, recorded just after 4:00pm.



Today's fire danger rating is extreme, and a total fire ban is in place until the end of the day.



"We're keeping a close eye on the weather conditions, those conditions are quite unpredictable," ESA Commissioner Georgeina Whelan said



Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 50 seconds 50 s A grass fire was extinguished near Yarralumla overnight. (Supplied: Nazmul Hasan)

Overnight, a grass fire was extinguished on Cotter Road near Yarralumla and Curtin, however it was an isolated incident and not linked to any bushfire activity.

Police said a 20-year-old Mawson man was apprehended near the scene of the fires, and had been charged with lighting a fire during a total fire ban.

What is a state of alert?



The ACT Government has declared a state of alert, effectively putting the territory on notice to be prepared for an emergency.



Firefighters on loan to other parts of the country where fires rage have been recalled to the ACT and other government service adjustments are being considered due to air quality concerns.

Many Canberrans appear to be preparing for fire, with supermarkets sold out of bottled water. ( Supplied: Matthew Guthrie )

Nature reserves will be closed until midnight, and some at-risk roads have been closed.



Canberrans appear to be taking the warnings from Government seriously; several supermarket shelves were yesterday stripped bare of bottled water.

The National Zoo and Aquarium has announced it will be closed tomorrow as a result of the extreme fire warning and continued poor air quality.

Staff will be on site to care for the animals.



How does this affect what's happening in Canberra?



As mentioned, a total fire ban is in place, but the message at the moment is: be alert, not alarmed.

But while business as usual should somewhat continue, the ACT's Chief Minister Andrew Barr has put pressure on the Summernats car festival to cancel planned burnout events.

Summernats has fire crews on standby, but the Chief Minister wants burnouts to be postponed. ( AAP: Lukas Coch )

"Our preference would be that they would come to that conclusion themselves as responsible mature adults, and I know that [Summernats co-owner] Andy Lopez is a responsible, mature adult," Mr Barr said.

"He has the capacity to alter his program to meet the conditions and he should do so."

But organisers are standing firm against Mr Barr's request, saying it was more about political optics than safety, and noting the precautions that are put in place around burnout events.

"There is no risk for bushfires or anything coming from what we're doing. We've put in the work and made the effort to make our activities safe, so we don't see any reason not to proceed," Mr Lopez said.

"Whilst it's Minister Barr's right to make those comments, he's made those comments without any consultation with the Summernats about what that would mean and how that would shake out."