- Thousands of people across New South Wales have been evacuated from their homes over the weekend as severe rainfall causes floods around Sydney’s west
- Some areas in the state have recorded almost a metre of rainfall since Thursday morning, with other areas recording 450 millimetres in three days
- For reference, Sydney typically averages around 130 millimetres of rain over the entire month of March
- Over 200 schools remain closed around New South Wales as the wild weather rages in what Premier Gladys Brejiklian has called a “one-in-100-year event”
- The rainfall is so severe that Sydney’s Warragamba Dam is spilling around 450 gigalitres of water per day to avoid overflowing
- This is exacerbating growing water levels in the already-swollen Hawkesbury-Nepean River
- Nevertheless, the NSW State Emergency Service (SES) said today flooding has started to ease around the Nepean River and an “All Clear” notice has been issued to residents in surrounding areas
- Meanwhile, the Bureau of Meteorology has also issued flood warnings to northern South Australia as severe rainfall also blocks roads across the area
Thousands of people across New South Wales have been evacuated from their homes over the weekend as severe rainfall causes floods around Sydney’s west.
The wild weather is expected to continue for several days as two intense weather systems clash tonight.
Astonishing levels of rainfall are breaking records across the state, with some areas recording almost one metre of rainfall since Thursday morning.
At Nelson Bay on the NSW Mid-North Coast, over 450 millimetres of rain fell in between Thursday and Sunday — the highest three-day total ever recorded in that location.
For reference, Sydney typically averages around 130 millimetres of rain over the entire month of March.
New South Wales Premier Gladys Berejiklian has called the events of the past week a “one-in-100-year event”.
Around 200 schools across New South Wales are closed today due to the ongoing weather event, with bus services around Penrith, Blacktown, and Hawkesbury paused because of flooding.
In other regions, buses are replacing trains, though Transport for NSW is urging people to work from home if possible, to avoid travelling through the storms and floods.
Nevertheless, flooding has started to ease around the Nepean River and the NSW State Emergency Service (SES) has issued an “All Clear” notice to surrounding areas — meaning evacuated people in these regions can now safely return home.
A harbour’s worth of water in a day
The rainfall is so severe that Sydney’s Warragamba Dam, a major water source for NSW, is spilling around 450 gigalitres of water per day just to avoid overflowing from the weather.
Sydney Harbour is estimated to hold around 500 gigalitres of water in total, meaning the dam is spilling almost the equivalent of one full Sydney Harbour every single day while the wild weather rages. The water spill is sending more water into the already-swollen Hawkesbury-Nepean River.
WeatherNSW said in a media statement on the weekend in order to avoid the spill event at the Warragamba Dam, it would have had to have been reduced to 25 per cent storage capacity before the severe weather event began.
The lowest level the dam has ever been reduced to was 38.8 per cent in 2004 during the Millennium drought.
“While WaterNSW is not authorised to lower the storage based on weather forecasts, significant pre-releases prior to a flood event could make flooding events more dangerous,” WeatherNSW said.
“Downstream tributaries could be inundated in a big rain event (as they are now), and the addition of extra water released from the dam could increase downstream impacts.”
It’s not just New South Wales
Heavy rain has caused flooding in the northern part of outback South Australia, too.
Roads and tracks used by freight trucks have closed across the region as Mount Dare recorded 118 millimetres of rain in 24 hours, while Moomba and Oodnadatta recorded 54 millimetres and 32 millimetres, respectively.
The Bureau of Meteorology has issued a flood warning for the area today, though at this stage the heavy rainfall is expected to move eastwards overnight.