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Storm hits Perth as ex-Tropical Cyclone Mangga delivers wild weather across WA, power cut to thousands

By Herlyn Kaur, Monday May 25, 2020 - 22:24 EST
ABC licensed image
The Canal Rocks Bridge in WA's South West was severely damaged when the storm blew through. - ABC licensed

A massive storm has wreaked havoc on southern coastal parts of Western Australia, including Perth, with thousands of homes without power, trees down and reports of widespread property damage.

State Emergency Services (SES) staff have answered hundreds of calls for help since Sunday night.

Most were for structural and roof damage with the majority of call-outs in the Perth metropolitan area and Mid West Gascoyne.

Wind gusts of up to 132 kilometres per hour were recorded at Cape Leeuwin, in the state's south-west, at 4:15am on Monday, while Kalgoorlie Airport recorded gusts of up to 94kph.

Western Power said on Monday night it was still working to restore supplies to about 10,000 properties from the Mid West to the Great Southern districts, with more than 6,000 of them in Perth.

At the peak of the storm, power was cut to about 65,000 properties. It was restored to the vast majority by early Monday afternoon, but conditions were preventing substantial repairs from being completed.

Western Power said about 13,000 customers in Kalgoorlie had their electricity cut off after a shed blew into a substation.

Relief arrives as storm passes

The damaging winds and severe weather lasted for much of the south of the state until well into Monday night before easing off as the storm passed.

The unusual weather was the result of a system from ex-Tropical Cyclone Mangga interacting with a cold front.

The official Australian cyclone season ended on April 30 and the Bureau of Meteorology (BOM) said while some cyclones were known to form in early May, it was rare to see one so late in the month.

BOM WA regional manager of severe weather Bradley Santos said the only comparable event was back in 2012, when a tropical system interacted with a cold front to produce severe weather over large parts of WA.

He said this storm was unusual because of its severity and the size of the area impacted.

"It certainly was a very rare event for WA because of the large area affected and the areas which were experiencing dangerous weather conditions," Mr Santos said.

"Many locations recorded wind gusts over 90kph, some over 100kph, and Cape Leeuwin recorded a gust of 132kph," he said.

"We also saw very heavy rainfall, but also storm surges along the west coast, and the tides rose much higher than the predicted tide.

"It's certainly not typical weather for this time of year."

Heavy rainfall, power outages across South West

The SES responded to more than 500 requests for assistance across the state from about 8:00am on Sunday, and Department of Fire and Emergency Services chief superintendent Danny Mosconi told ABC Radio Perth the majority had come from the Perth metropolitan area. 

"Pretty much the whole metro area and in fact most of the state … [it's been] pretty widespread," he said.

"The size of the storm saw crews assisting people from Exmouth all the way down to the south coast.

"We did see some significant damage to homes and property and a high number of callouts in the southern suburbs of Perth like Canning Vale, Lynwood and Thornlie.

"The roof was blown off a tavern in Canning Vale, a patio demolished and blocked access to a house in Lynwood, and a garage collapsed at a house in Thornlie. We also had roofs off commercial buildings in Bedford and St James.

"Fortunately, although a large number of people needed assistance, we didn't see too many reports of severe damage.

"I want to thank those members of the public who heeded the warnings and prepared their properties, that's a critical part of reducing the workload on the SES volunteers."

BOM forecaster Noel Pusey said the central Pilbara coast had received 30–40 millimetres of rain, while Learmonth had 59.6mm.

"In the south, they had some pretty reasonable falls of 51–52mm around the South West capes, [and] wind gusts, the strongest one we've seen was 132kph at Cape Leeuwin," he said.

"That low definitely caused a quite a strong pressure gradient through there and pretty decent westerly gales through there, and I expect the tides were higher than normal through the Geographe Bay area but right along the west coast."

The Canal Rocks walk bridge, in WA's South West, was badly damaged by heavy swells and high tides. It has been closed to the public.

Parks and Visitor services coordinator Ben Tannock said it was not clear if the bridge sustained any structural damage.

"Once the conditions settle, we will get a structural engineer out there," Mr Tannock said.

The same bridge was damaged by stormy weather several years ago.

"It's obviously in a high-energy part of the coastline so, when we get these big storms, it is prone to the effects of that high energy," Mr Tannock said.

Hills cop heaviest rain in Perth

Strong winds were expected to continue throughout the south-west corner of the state, BOM spokesman Neil Bennett said.

"The strongest winds now are likely to be down in that south-west corner with a very deep low pressure system … really dominating the pattern down there for the next day," he said on Monday.

The Perth metropolitan area was warned it would face wind gusts of up to 80–90kph, with a small risk of hail, mainly in the city's south-eastern suburbs.

"Perth itself, the heaviest falls have been up in the Hills — we've had falls of 30mm up through Bickley and Perth itself close to 20mm so far," Mr Bennett said.

The Wheatbelt had seen falls of about 10–15mm, with coastal areas receiving about 20–30mm.

"Margaret River [has had] around 50mm and 60mm up in Exmouth," Mr Bennett said.

But he said Pilbara coastal areas had received the heaviest falls because it was still dealing with "all the tropical air up there".

Storm surge sees huge waves erode beaches

The storm has caused significant erosion at Port Beach, near Fremantle.

A section of the car park has fallen into the ocean, and a large area around it has been fenced off.

, and is one of a number of the state's coastal areas where relocation of buildings has been suggested.

The State Government recently contributed $200,000 to build a rock wall to try to shore up the long-degraded coastline.

But that part of the beach where there is no rock wall has suffered badly from the storm surge and large swells.

The dunes at Cottesloe Beach have also been eroded by the storm, as waves wash away the sand.

Big storm swells crashed into the groyne on Monday morning and into the iconic sea pylon in the water off the beach, completely submerging it at times.

The storm surge and high tides pushed the ocean right up the beach to the bottom of the dunes, leaving them being eroded hour by hour by the swirling mass of water.

Earlier, a group of elderly swimmers braved the water and ferocious wind for their traditional morning plunge.

Onlookers came throughout the day to marvel at the ocean’s fury and watch those brave or crazy to venture in. 

Impact on Geraldton almost 'cataclysmic'

Geraldton Mayor Shane Van Styn said the storm had a significant impact on the Mid West city.

"The combination of events that the city faced [on Sunday], all but cataclysmic would be the way to describe the event," he said.

"We were fighting not just large dust storms, not just large wind events, we were dealing with coastal inundation, tidal surges, we had multiple bushfires on the go at the same time, it was quite a hairy day with a whole range of city services under threat.

"[But] overall, compared to larger scale emergency events … the city came out relatively good.

"A lot of our rural roads … have large trees over them, large volumes of sand out on some of those bituminised rural streets are going to require clearing.

"We continue to monitor things like asbestos around town, a lot of fences are down."

Huge swells, erosion at Busselton

Busselton has been one of the worst hit areas in the South West, with widespread power outages, fallen trees and minor structural damage reported.

Mayor Grant Henley said the high tides and swell had also caused a lot of damage along the Busselton coast.

"There's not a lot of beach left," he said.

"There's a significant amount of erosion and impact on coastal infrastructure."

The strong winds have also forced the closure of the city's prime tourist attraction, the Busselton Jetty.

Busselton Jetty chief executive Lisa Shreeve said a safety inspection would take place.

"We had 106kph wind gusts at the end of the jetty at 2:00am [on Monday], but at this stage everything looks fine," she said.

South West crops destroyed again

The storm has come as a costly blow for South West fruit and vegetable growers.

Some had only just replanted their crops after a storm tore through the region last month.

"We had a storm about two-and-a-half weeks ago, and it destroyed them," said Joe Castro, who grows carrots, potatoes and onions at his farm in Myalup.

"We replanted, now [the plants] are just coming through and [this storm has] smashed them again."

He said he would now have to replant his carrot crop again, at significant cost.

"Probably going to cost you $30,000-$40,000 to replant them twice, and potential income in the future," he said.


© ABC 2020

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