Sydney weather: Flooding, more beach erosion possible for NSW as another winter storm looms
NSW may be in for another powerful winter storm bringing heavy rain and a coastal storm surge with another east coast low projected to form off the coast.
The worst coastal erosion impacts occur when there are a series of storms over a short period of time
OEH
Weather models are forecasting the potential for heavy rain and gale force winds along the state's south coast from Sunday into early next week, meteorologists say.
Collaroy's beach front houses were among those hardest hit from the early June event.
Collaroy's beach front houses were among those hardest hit from the early June event. Photo: AAP
"I think at the moment, the major concern would be just the rainfall," Peter Gajewski, a senior forecaster at the Bureau of
There are likely to be widespread falls of 100-150mm on Sunday and Monday, and "in some parts it will be more", Mr Gajewski said.
At present, the bureau's four-day rain forecast from June 18 onwards suggests the state's south coast is in for a soaking while Sydney too may also collection as much as 100mm of rain. (See chart below.)
Brett Dutschke, a senior meteorologist at Weatherzone, said models were still to "get a grip" on the timing and location but another east coast low is looking increasingly likely.
"Where the biggest wind, surf, rain and beach erosion will be is difficult to tell," Mr Dutschke said.
While the potential winter storm is unlikely to be as widespread or as long-lasting as the monster east coast low that hit the state at the start of June, catchment areas will be sodden and many beaches have already been stripped of their protective sand buffers.
"It's likely there'll be some beach erosion, with damaging surf and wind," Mr Dutschke said, adding that coastal impacts may be from next Monday onwards.
The aftermath at Collaroy Beach even after 12,000 sandbags were laid.
The aftermath at Collaroy Beach even after 12,000 sandbags were laid. Photo: Peter Rae
Authorities may also want to expedite the removal of any debris from the previous storm, he said.
"You don't want to have (that debris) lying around in rivers or gutters," Mr Dutschke said. "You want that water to running as freely as possible from the rivers out to the sea."
The bureau's Mr Gajewski said a dominant high-pressure system over the Tasman was leading to the relatively warm temperatures across eastern Australia.
Unusually warm sea-surface temperatures off south-eastern Australia have the potential to give storms systems extra moisture. The ocean warmth "is another very important factor", Mr Gajewski said .
While most catchment areas are particularly wet after the previous event, the likelihood of more rain will see some reservoirs start to spill, Mr Dutschke said.
Warragamba Dam, Sydney's major water storage, was sitting at 97.7 per cent full as of Monday, the government's website said.
The 24 hours to 9am on Sunday, June 6, was the wettest day on record for eastern NSW, with 19 of the state's 20 coastal catchments recording at least 70mm of rain, the bureau said.
On the plus side, many inland regions of NSW and Queensland can expect more good rainfall as the system moves eastwards, the meteorologists said.
Record waves
June is typically the most active month for east coast lows, cyclonic systems that form off the eastern Australian coast and bring heavy rain and storm surges if they linger near land.
Authorities are still assessing the full impact of the previous storm that caused widespread damage from south-eastern Queensland down to Tasmania.
At this stage, the coming event is expected to be faster moving, resulting in more localised heavy rain and beach erosion, particularly to the NSW south coast.
Still, as the Office of Environment and Heritage's summary of impacts shows, many coastal regions remain vulnerable to damage following record swells earlier this month. The 17.7 metre maximum wave height recorded on June 6, for instance, surpasses the previous mark by almost three metres.
"If councils consider that they have structures – either public or private – at risk and there is a public safety risk, they should employ a coastal engineer or structural engineer to assess the stability of structures," the OEH has told councils.
It noted that high tides are expected about every fortnight during winter, which if combined with another east coast low, would likely lead to further erosion impacts for coast communities.
A separate OEH survey of the impacts of the early-June monster storm showed that even in regions with limited erosion, most beaches lost considerable amounts of sand.
Sydney's northern beaches attracted much of the public's attention as areas such as Collaroy-Narrabeen lost about 50 m of beach, exposing about 10 homes to risk of collapse... |
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