NSW is no stranger to floods, but this one was different

The devastating flood damage wreaked by Tropical Cyclone Debbie has left many residents in northern New South Wales facing an enormous cleanup that could take months.

Lismore received a drenching from the
tail end of Tropical Cyclone Debbie. 

Any Lismore local will tell you that flooding is a fact of life in the Northern Rivers. In the floods of 1954 and 1974, the Wilsons River rose to a record 12.17 metres. This time around, the river peaked at 11.59m, breaching the flood levee built in 2005 for the first time.

So what are the conditions that caused those historic floods? And are they any different to the conditions of 2017?

Like the current flood, cyclonic rains also caused the 1954 and 1974 events. But unlike those past events, both of which were preceded by prolonged wet weather, almost all of the extreme rainfall from ex-Tropical Cyclone Debbie fell within 24 hours.

More interesting still is the fact that we are not currently experiencing La Niña conditions, which have historically formed the backdrop to severe flooding in eastern Australia.

Read the piece on The Conversation by an ARC DECRA Climate Research Fellow from the School of Earth Sciences at the University of Melbourne, Joelle Gergis - “NSW is no stranger to floods, but this one was different.”