News

Dry lightning causing fires in eastern Australia

Thunderstorms with little to no rainfall have been igniting fires and causing damaging winds in parts of eastern Australia this week.

On Wednesday, numerous fires were triggered by dry lightning as high-based severe thunderstorms tracked over central NSW. These storms also caused damaging wind gusts in some areas.

The satellite loop below shows a cloudband moving over NSW on Wednesday afternoon and evening. Clear skies through the earlier part of the day allowed ample surface heating, helping fuel instability and trigger high-based thunderstorms embedded in the cloudband.

Image: Visible satellite imagery, radar (green) and lightning (purple) on the afternoon and evening of Wednesday, October 8, 2025.

Beneath the cloudband, hot and dry northwesterly winds made for a very dry sub-cloud layer that rapidly evaporated any precipitation falling from the cloudband and its thunderstorms.

By the time the first round of thunderstorms had moved out over the Tasman Sea, the most rainfall accumulated in a rain gauge was about 3 mm at Shooters Hill, south of Oberon.

Image: DTN Quantitative Precipitation Estimate (QPE) and observed rainfall since 9am across the region to 9pm.

Wednesday's mostly dry thunderstorms followed a relatively dry spell in the preceding 4-5 weeks, which resulted from a rare Sudden Stratosphere Warming (SSW) event above Antarctica in September and early October. This prolonged lack of rain has primed the landscape and vegetation in the region for fires.

DTN’s Total Lightning Network (TLN) recorded over 16,500 lightning strikes within 300km of Lithgow between 4pm and 10pm on Wednesday. Of these strikes, 2,545 were cloud-to-ground lightning capable of igniting fires.

Image: The red squares and crosses show the 16,558 lightning strikes detected within 300 kilometres of Lithgow between 4pm and 10pm AEDT on Wednesday, October 7, 2025.

The NSW Rural Fire Service was managing over 40 active fires across NSW on Wednesday when response to at least two additional bushfires was needed following the passage of the thunderstorms in the Oberon region.

The very dry layer below the cloudband, along with strong winds in the upper parts of the atmosphere also brought damaging wind gusts to the region. The strongest wind gusts reported were:

• 98km/h at Bellambi (Illawarra)
• 96km/h at High Range (Illawarra)
• 82km/h at Mudgee (Central Tablelands)
• 80km/h at Cessnock (Hunter)
• 78km/h at Orange (Central Tablelands) and Merriwa (Hunter)

Strong and gusty winds help fan bushfire flames and promote erratic, unpredictable fire behaviour, making it difficult for fire management agencies to contain them.

Active thunderstorm period in the coming days

Unfortunately for fire management agencies, thunderstorms are once again on the cards for central and northern NSW on Thursday, before moving into northeastern NSW and Queensland on Friday.

Widespread severe thunderstorms are expected to develop with a broad low pressure trough over the Northern Territory, northern South Australia, NSW and Queensland this weekend. Enhancing this thunderstorm activity will be very warm air across central and eastern Australia, bringing an elevated bushfire risk period lasting until early next week.

Image: GFS thunderstorm forecast at 2pm AEDT on Sunday, October 12, 2025.

Be sure to check the latest weather and fire warnings in your area over the coming week.