New data shows could be battered by cyclones for the next 30 years, with weather conditions mirroring the horror 1950s to 1970s cyclone season.
A Journal of Southern Hemisphere Earth Systems report in 2020 found a link between changes in the Interdecadal Pacific Oscillation (IPO) and cyclone activity in NSW.
When the IPO dips into a negative phase, NSW sees more cyclones.
The last negative IPO was recorded from the 1950s to 1970s when NSW saw more cyclones than ever recorded, with an average of one system striking every two years.
Australia’s IPO has entered a negative phase similar to what caused massive cyclone damage and flooding in NSW in the 1950s to 1970s (pictured, residents in Maitland, 1950)
A low IPO in the 1950s to 1970s lead to increased rainfall in NSW (pictured, a map of where rain was above average – blue – and below average – red – in 1950 and 1974)
NSW sees increased cyclone activity when the IPO enters a negative phase (above) where the water is colder along the equator and warmer either side
During that period, NSW also saw its wettest year, before 2022, in 1950 with more than 2,100mm falling in Sydney alone.
The majority of Australia’s cyclones batter north and central Queensland during the early months of the year.
Most of the cyclones to reach NSW tend to fall on the northern coast but during the heightened cyclone season some made their way down to Sydney.
The worst cyclone to hit NSW’s capital was TC119 in 1950.
The cyclone reached the harbour city as a category one system and bucketed 114mm in 24 hours.
It claimed seven NSW lives and wrecked seven yachts in Sydney’s harbour.
Most of Australia’s cyclones fall in Queensland and occasionally northern NSW (area pictured in green) but a IPO-driven cyclone season could see cyclones reach Sydney
Two cyclones affected Sydney in the 1950s to 1970s and caused extensive damage and floding (pictured, residents in Maitland, 1950)
A second cyclone that crossed NSW’s coast near Tweed Heads also dropped more than 100mm of rain over Sydney in 1954, 바카라사이트 triggering devastating floods.
The same cyclone caused disastrous floods in Lismore and Casino and claimed a total of 30 lives.
It is the deadliest cyclone on record in NSW.
In the 48 years since the last 1970s cyclone, only Cyclone Nancy (1990) and Ex-Cyclone Oswald (2013) have reached NSW.
Both cyclones caused extensive flood and storm damage that cost hundreds of millions of dollars to repair.
Data shows Australia’s current IPO has again dipped into a negative phase, even lower than the 1950s record, and could stay there for several decades.
Most of the cyclones to cross into NSW only affect the northern coast but during the 1950s and 1970s reached much further south (pictured, all cyclone tracks recorded in NSW from 1887 to 2013)
In 1950 a devastating category one cyclone reached Sydney and claimed seven NSW lives (pictured, a newspaper excerpt from 1950 about the cyclone)
The Bureau of Meteorology said cyclones tend to affect NSW in four ways:
- A cyclone moves in on NSW’s coast (Bryon Bay in 1990 and Tweed heads in 1954)
- A cyclone moves through Queensland and reaches NSW (1964 when a cyclone reached Coffs Harbour and 1950 when one reached Sydney)
- A cyclone stay s off NSW’s coast but causes huge swells (1998 in Byron Bay and 1974 in Sydney)
- A cyclone hits or lands near Lord Howe Island or Norfolk Islands (1973, 1974, 1997)
Recent changes in climate have reduced cyclone activity worldwide but history tells us a low IPO means a potentially devastating cyclone in NSW is possible.
A modern cyclone in NSW would likely be far more devastating than previously recorded with the state now highly populated but lacking cyclone-proof infrastructure.