Fire crews battling the Orroral Valley fire are bracing for deteriorating conditions this weekend with strong winds and hot temperatures forecast.
Friday and Saturday are shaping up as the worst days on the firefront with wind gusts of up to 50km/h and the temperature reaching 42 degrees.
While the conditions forecast for later this week are expected to be severe, winds may not be as dangerous as those seen during the devastating 2003 bushfires, according to a bushfire expert.
Former CSIRO bushfire expert Phil Cheney said winds were much stronger during the bushfire disaster 17-years-ago, which killed four people and destroyed almost 500 homes.
"The forecast [for the Orroral Valley fire] isn't as bad as 2003 when the fire burnt into Canberra because of the wind.
"The wind gusts may be up on Saturday but the mean speeds are forecast to be 30km/h. While we might get gusts twice that amount, the mean speed in 2003 was 65km/h."
The recent bushfires in the Orroral Valley has brought back memories of the 2003 fires for many Canberrans, which also started in the Namadgi National Park.
While the forecast may change in coming days, Mr Cheney said Canberra suburbs weren't likely to come under attack in the same way they did previously.
"We certainly have to be cautious, but at the moment, we're not exposed to the same potential of fires running into the suburbs to the extent of 2003," he said.
Chief Minister Andrew Barr said the fires in the Namadgi National Park are the worst the city has seen since 2003 and urged Canberrans to prepare for the worst.
"There are more challenging days ahead," Mr Barr said on Wednesday.
ACT Emergency Services Agency commissioner Georgeina Whelan said the ACT had learnt lessons from the 2003 disaster and the Canberra community was seeing an effective response to the ongoing fires.
"What we're seeing nationally and across the ACT is that we have conditions conducive to bushfire activity, some are similar to 2003," she said.
"What we're seeing in 2020 is the fact that we have unprecedented bushfire behaviour, as a result of the weather, the drought and the volume of fire activity that's across our landscape."
Hot and dry conditions this week have allowed the Orroral Valley bushfire burning in the Namadgi National Park to spread rapidly.
In the first 48 hours since the fire started on Monday afternoon, the fire grew to more than 10,000 hectares.
The Bureau of Meteorology says the weather pattern forecast for Friday and Saturday is driven from north-west and westerly winds that have moved across the country now impacting along the eastern states.
Meteorologist Shuang Wang said the severe conditions were brought on by a trough moving ahead of a cold front, bringing with it the strong winds.
"Temperatures are going to increase for the next few days in Canberra," she said.
"There will be strong north-westerly winds on Saturday, between 40 and 50km/h.
"It will then drop later in the evening but it will still be around 20km/h, but the average speed that day will be around 35km/h."
Wind gusts are predicted to be stronger around elevated areas of the ACT near the Namadgi National Park
The strong winds are expected to last until into Sunday, before a southerly change will bring with it a storm the chance of rain.
"There will be elevated fire danger on Friday and Saturday," Ms Wang said.
"But by Sunday afternoon, the winds will drop to 25 to 35km/h."