Firefighters in the ACT will face rising temperatures and increasingly dangerous fire weather during the next several days, with rain unlikely to arrive until Sunday.

A fire burning in the Orroral Valley to the south of Canberra grew quickly on Tuesday as hot and windy weather affected the ACT. At Canberra Airport, the temperature climbed to 34 degrees in the afternoon and wind gusts reached up to 43km/h in the evening.

These conditions allowed the Orroral Valley fire to triple in size in the space of just 12 hours. At 10:23am, it was 2576 hectares in size and by 10:30pm, it had scorched 8106 hectares of land, according to the ACT Emergency Services Agency.

#Timelapse from last night looking towards #Booroomba #orroralvalleyfire #bushfiresAustralia #canberrafire #namadgi #bushfires We left as we could see the dreaded #smoke rolling in. #sonya7iii pic.twitter.com/7mglXc6Vfh

— Shaun Humphreys (@shaunh) January 28, 2020

Part of the reason the Orroral Valley fire flared up on Tuesday evening was the arrival of a gutsy easterly wind change, which helped fan the flames and caused the fire to start spreading in a new direction. Fortunately, cooler air behind this easterly change saw the fire downgraded from Emergency Warning to a Watch and Act status shortly after 11pm on Tuesday. However, the fire was still uncontrolled on Wednesday morning and by 7:29am, it had grown to 9500 hectares in size.

Looking ahead, temperatures are likely to climb in the ACT during the next four days as northwesterly winds transport a mass of hot air from central Australia towards the nation's southeast.

Image: Forecast surface wind and temperature showing hot air being transpotred over southeastern Australia on Saturday.

Canberra is forecast to reach 36 degrees on Wednesday, 39 degrees on Thursday and 42 degrees on Friday and Saturday. This building heat will cause Very High fire danger ratings in the ACT until Friday and Severe fire danger from Saturday.

A low pressure trough passing over the ACT on Sunday will drop temperatures by several degrees and possibly cause showers and thunderstorms. While the rain will be welcome, any lightning brings a risk of starting new fires.

Visit https://esa.act.gov.au/ for the latest information on fires in the ACT.