A strong high pressure system over southern Australia created a settled autumn weather window across NSW this weekend, allowing fire crews to carry out hazard reduction burns in parts of the Blue Mountains National Park and Royal National Park. 

 Fig. 1: MSLP analysis at 10am AEST on Saturday 9th May 2026, showing a strong high pressure system south of the mainland and a broad ridge extending across NSW. Image: BoM.

The setup aligns well with the NSW RFS guidance for low intensity hazard reduction burning, which points to temperatures below 25°C, relative humidity around 50% and rising, winds below 15 km/h in the open and stable atmospheric conditions. These conditions help keep fire behaviour slow and manageable, while still allowing dry surface fuels to burn. However, the same stable weather that makes burns easier to control can also trap smoke near the ground, causing temporary air quality and visibility impacts in nearby communities. 

Burns were carried out on Saturday 9th May and were also planned for Sunday 10th May, taking advantage of this stable weather pattern while fuels were dry enough to burn but winds and temperatures remained manageable.  

Fig. 2: Smoke plumes from hazard reduction burns in the Blue Mountains and near Royal National Park were visible from space on Saturday 9th May 2026, with smoke drifting eastwards over the Tasman Sea under a stable high pressure pattern. Image: NASA Worldview, using MODIS Terra/Aqua Corrected Reflectance True Colour imagery.

The burns may cause short-term impacts across affected areas, including visible smoke, temporary park and trail closures, restricted access and reduced visibility on nearby roads. These measures are put in place to keep the public safe while crews manage the burns and assess the area afterwards. 

Fig. 3: Smoke from hazard reduction burning seen from a window near Royal National Park. Image: Maryam. 

Fig. 4: Smoke haze affecting visibility along the Princes Highway near Royal National Park during hazard reduction burning on Saturday evening. Image: Transport for NSW.

While hazard reduction burns can bring temporary smoke and access impacts, this weekend’s high pressure pattern provided the type of mild, stable weather window needed to reduce fuel loads before more dangerous bushfire weather returns later in the year.