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Sydney faces heightened flood risk over summer, BOM and emergency services warn

Matt Bamford, Monday November 16, 2020 - 07:34 EDT
Audience submitted image
The BOM and SES are warning Sydney faces a heightened flood risk over summer. - Audience submitted

If last summer was defined by devastating bushfires, the Bureau of Meteorology and emergency services are warning that floods and storms are the weather patterns to watch out for in the coming months.



With dam levels already above 90 per cent and a La Niña phenomenon expected to bring more rain to the east coast, Sydneysiders are being urged to prepare for the possibility of a damaging deluge.

There are a series of practical steps residents can take to minimise their risk.

Why is there a heightened risk?

Months of rainfall from as far back as February have caused dam levels to rise and moisture content in the soil to increase, according to the BOM's Agata Imielska.

"Our dam levels in the Greater Sydney area are at just over 95 per cent capacity, with Warragamba Dam sitting at just over 97 per cent," she said.

"If we get any heavy rainfall in that area it's more likely to produce flooding because of the limited capacity for our soils to absorb that moisture."



Compounding these factors is the onset of a La Niña, a climate-influencing phase of the El Niño Southern Oscillation (ENSO), which describes ocean and atmospheric circulations over the Pacific Ocean.

During a La Niña phase, Australia's northern waters are warm with increased convection.

This allows more moisture to be lifted into the air than normal, typically resulting in increased rain and warm temperatures at night.



"If we look to our next three months we are expecting La Niña to continue through summer with above average rainfall across the Sydney area and large parts of Australia," Ms Imielska said.

"Australia really is the land of drought and flooding rains.

"A lot of us still have the dry conditions and bushfires at the front of our mind but really we need to be looking to that quite drastic shift from drought conditions to having flood risks."



What areas could be affected by flooding?

Residents across the Greater Sydney region should be alert to the dangers of storms and flooding but there are key locations that are more vulnerable.

Suburbs around the Nepean, Hawkesbury and Georges rivers are most at risk of being inundated.

New South Wales State Emergency Services (SES) Commissioner Carlene York has been preparing her team to assist residents in need.

She said staff would be on alert and ready to help in the event of a heavy downpour but there were also a number of precautions residents could take to prepare now, and in the lead up to a likely flood event.



Make a flood plan

Coming up with a home emergency plan in the event of a flood is an essential part of preparations.



Obtaining a copy of your is key to finding out the location of problem areas, evacuation routes and relief centres.

"Think about what you need to take in an emergency kit," Commissioner York said.

An can include important documents, a portable AM radio with spare batteries, a first aid kit, a torch, candles and waterproof matches.

"Tie things down, make sure your gutters are clean and be aware of the conditions of trees around your home," Commissioner York said.

If a flood warning is issued, residents should identify the safest route to the nearest relief centre and leave with plenty of time.



Residents can also decide which items they want to put in a higher spot and think about what to do with the contents of fridges and freezers.

Commissioner York said pet owners should take notice of the .

It recommends planning for what to take, how to transport your pets and understanding where the animals can go during an emergency.

If you need to evacuate

Stay calm, follow your plan and listen out for updates.

Along with an emergency kit, residents can take warm clothing, essential medications, a mobile phone and charger and waterproof bags.

You can raise furniture and other valuables onto beds or into roof spaces, turn off power and gas and place sandbags in the toilet bowl to prevent sewage backflow.



When leaving, do not walk or drive through flood water — just 30 centimetres of water can sweep away a car.

Keep away from fallen powerlines and let family and friends know your location and where you are going.

Keep listening to your local ABC Radio station on a battery-powered radio, listen online or via the ABC listen app for updates and instructions.

Those caught in floodwater should call for help immediately from the SES on 132 500 or triple-0 in a life threatening situation.


- ABC

© ABC 2020

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