Australian weather: Town at risk of worst flood in 155 years

A historic flooding catastrophe that claimed 30 lives 155 years ago could repeat itself in the coming months, experts have warned.

A historic flooding catastrophe that claimed 30 lives 155 years ago could repeat itself in the coming months, experts have warned.

The Hawkesbury-Nepean river is at heightened risk of a flood disaster similar to the one that happened in 1867, according to the Sky News Weather team.

The historic disaster saw 30 people lose their lives as floodwaters reached 20 metres in Windsor, six metres higher than the flood peaks experienced in the region earlier this year.

Almost 500 homes had to be evacuated, while houses were swept away and most of Emu Plains was underwater during the 1867 floods.

Sky Weather meteorologist Rob Sharpe said a record-breaking flood was likely to smash the vulnerable river system again.

“The question is when and the chances at the moment are the highest they have been for decades,” Mr Sharpe said in the documentary Underwater: Forecast for Disaster, available to stream on Flash.

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Hawkesbury-Nepean at risk of worst flood in 155 years. Picture: NCA NewsWire / Damian Shaw

The 1867 Nepean River flood as depicted in The Sydney Morning Herald on April 24, 1867. Picture: Penrith City Library.

If a similar flood occurred today, the SES determined that around 90,000 people would need to be evacuated.

About 12,000 homes would be inundated and the damage bill would reach $5 billion.

Sky Weather chief meteorologist Tom Saunders said the team found that 4000 homes would become unliveable while close to 40,000 people would need temporary accommodation.

“The Hawkesbury electrical substation, and possibly the Penrith substation would be flooded and badly damaged, meaning up to 50,000 non-flooded properties would be without power for up to three months,” Mr Saunders explained.

“Two hospitals would need to rely entirely on emergency generators, while raw sewage would flow into the river for months.”

Underwater: Forecast for Disaster examines the potential catastrophic impacts on the Western Sydney region should the tragic events of the historic 1867 Hawkesbury-Nepean flood disaster be repeated.