Remnants of ex-Tropical Cyclone Mangga whip up 100km/h wind gusts, dust storms and heavy rain as Perth and state’s south prepares for onslaught
Some 50,000 homes in Western Australia are still without power as the state continues to be battered by wild weather for a second day in a row, in a “rare event” described as a “once-in-a-decade” storm.
The state has experienced the wildest autumn weather in years, as the remnants of ex-Tropical Cyclone Mangga collided with a cold front and trough, whipping up gusts of about 100km/h.
While large sections of the state’s coastline were hit over the weekend, the south of the state was set to bear the brunt of the storms on Monday, with strong winds, heavy rain and potential flooding.
There were 407 emergency calls to the Department of Fire and Emergency Services in the 24 hours until Monday morning, after roofs were ripped off and trees felled as wind gusts whipped the state’s northern coastal regions.
Strong winds raised dust through large areas of the Gascoyne and Central West, blanketing many towns including Geraldton, the Bureau of Meteorology said.
Many areas along the west coast recorded their highest tides of the year.
The wild weather caused a large number of households to go without power, with powerful winds making it impossible to repair some section of the grid until the storm subsided.
The extreme weather peaked on Sunday, with 62,000 homes experiencing a blackout. Although power was restored to some homes, new damage from debris continued to keep the overall number high.
Western Power said as of 6.30am Monday, 20,000 people in the south were without power, with Margaret River and Dunsborough the worst-hit, and 13,000 people across metro Perth.
“Kalgoorlie has 15,000 homes and businesses impacted by storm outages after a shed was blown into one of our substations in the area,” Western Power said in a statement. “Crews are currently working to remove the shed from electrical infrastructure and assess the damage before repairs can be carried out to restore customers.”
The Bureau of Meteorology warned of possible flooding in Perth on Monday, with high tides expected along the coast.
“Our general rule of thumb is when the tide is over 1.6 meters there can be some inundation along Swan River, and the tide is current 1.73m,” said duty forecaster, Bob Tarr.
“Other places along the rest [of the] coast, like Geraldton, is running more than half a metre about the normal tide, and Jurien Bay is about two-thirds of a metre above.”
He said this could cause significant erosion at beaches.
“Some places I would expect are going to see not a lot of beach left after this storm.”
Waves of more than eight meters were also expected in the south-west.
Rainfall totals in the Pilbara and western Kimberley coastal areas were likely to be around 20-40mm, with isolated falls of up to 100mm in coastal areas from Cape Leveque and Broome down to Kalbarri.
Heavy rain was also likely down the west coast from Kalbarri to Albany, with totals of around 20-30mm and some isolated falls up to 60mm.
Much of the agricultural areas were likely to receive falls in the range of 10-20mm.
Residents in the south-west were warned to unplug electrical appliances, avoid using landline phones if there was lightning, and stay away from windows.
Motorists were told to watch for hazards and to not drive into water of unknown depth and current.
Tarr said wild weather would shift further south on Monday afternoon and ease overnight, with warnings likely to be lifted by Tuesday morning.
Western Australia was not the only state to take a battering. A complex low moving across the south Tasman Sea over the weekend created rough and dangerous conditions in waters around the New South Wales coast.
Helen Reid, a meteorologist with the weather bureau, said this was likely to ease on Tuesday.
“Tomorrow and into Wednesday that low will weaken and move further east. That will mean the winds will be a little less of a problem,” she said.
On Sunday 40 shipping containers were lost overboard off the NSW coast after a ship rolled during heavy seas while travelling from China to Australia.
About 10.45am the Australian Maritime Safety Authority was notified that a container ship had lost cargo overboard off the state’s coast.
The Singapore-flagged container ship APL England experienced a temporary loss of propulsion during heavy seas about 73km south-east of Sydney just after 6.10am. The ship was en route from China to Melbourne.
“The ship’s power was restored within a few minutes but during this time the ship reported that it was rolling heavily, causing container stacks to collapse and several containers to fall overboard,” the statement said.
The APL England’s master has reported some 40 containers were lost overboard and 74 were damaged.
“At this stage it is unknown whether there will be any shoreline impacts associated with this incident and AMSA is working with NSW Maritime to monitor the situation and develop an appropriate response,” the authority said.
The Australian Transport Safety Bureau said on Sunday it will investigate the loss of containers.
“ATSB transport safety investigators will meet the vessel when it arrives in port in the coming days to survey damage to the vessel and container stacks, interview the crew and retrieve available recorded data,” the bureau said in a statement.
Investigators will also analyse weather information and review the operator of the ALP England’s loading systems.
Guardian