Light drizzle after a long dry spell is to blame for a series of fires that have cut power to tens of thousands of homes in Western Australia, while extreme heat is set to dominate the remainder of the long weekend in Victoria and South Australia.
A spokesperson from Western Power said dozens of pole top fires had left 38,000 homes in the Perth and midwest regions of WA without power on Saturday morning.
Western Power’s executive manager for asset operations, Zane Christmas, explained the fires could occur in “light drizzling rain or misty, damp conditions when a combination of dust and pollution builds up to create paths or ‘tracks’ on the insulators.
“This tracking electricity can heat poles to a point where they smoulder and burn,” said Christmas.
Overnight on Friday, Perth received 2.4mm, just enough to dampen the dust that had gathered on electricity poles over months of dry weather. Only 15mm of rainfall has fallen in the city in almost three months, Bureau of Meteorology senior meteorologist Dean Narramore said.
Narramore said the phenomenon was “a strange one”, but “happened around the country from time to time,” adding that heavier downpours usually washed pole top dust away.
He said showers in the state’s southwest had brought some relief to fire fighting efforts. Hot weather and strong winds had fuelled several bushfires in WA, including one in the Wheatbelt region that had burnt about 11,000ha by Saturday afternoon.
Perth’s reprieve from high temperatures was forecast to end on Tuesday, when the city’s temperature was due to climb again, eventually reaching 41C on Thursday.
Heat from the southern half of the state was forecast to move eastwards, delivering temperatures of well over 40C to parts of South Australia on Sunday and arriving in Victoria on Monday.
In Melbourne, the mercury was expected to top 42C on Monday, with temperatures in the mid-40s expected in the north of the state and inland New South Wales.
“With that heat it’ll also be windy, so we’re also looking at extreme fire dangers for parts of South Australia and much of western and central Victoria on Monday,” Narramore said.
“So, another spike fire and heat day for pretty much [the whole of] southeast Australia.”
The same front was then forecast to head north to eastern NSW, with the temperature set to reach the low 40s in western Sydney on Tuesday before a cool change.
“It’s getting hot again, in the south-east and the east, and then it’ll cool down midweek and probably get hot again this time, next week,” Narramore said.
South-eastern Queensland’s heatwave gave way to calmer conditions after storms on Friday night, with 31C and 30C expected in Brisbane on Sunday and Monday.
Rain and thunderstorms possibly bringing heavy rainfall were expected to develop in the tropical north of the state at the beginning of the week.
