Why were people caught out in the floods?
MOTHER Nature had the last laugh. The flood's speed was almost unprecedented - but it echoed a previous event in 1954.
The flood was caused by 24 hours of non-stop, heavy to extreme rain falling in a concentrated north-south corridor running directly over the Nightcap and Border Ranges which feed the Wilsons and Tweed Rivers. The rain started at about 1am Thursday and ended almost exactly 24 hours later.
Up to 700mm of rainfall fell in 24 hours in some locations. Lismore itself had an estimated 400mm.
"It was remarkable the amount of rain that fell in that 24 hour period," said local severe weather expert Michael Bath (operations manager with the Early Warning Network, a severe weather forecasting service).
Mr Bath likened the event to the 1954 flood, when a single ex-tropical cyclone dumped unprecedented rain in a short 24-hour burst on an already wet catchment.
Also, the bulk of the rain fell in the western arm of Lismore's catchment (Leycester Creek), which is always the driving force of major flood events in Lismore.
The massive rainfall may have caught the Bureau of Meteorology and the SES (which relies on the BOM's weather predictions) off guard.
In the space of four hours, after lunch on Thursday, the weather warnings ramped up from a typical 'do-nothing' moderate flood to a historically significant major flood which would overtop the levee at 11m.
At 4.30pm, the SES confirmed it would exceed the 2005 and 2001 floods, while still forecasting more rain.
It wasn't until 5.40 pm that the first evacuation order was issued by the SES for Lismore, North, South and CBD.
Then at 9.44pm on Thursday night, this was ramped up again to an 11.5m peak (ultimately closer to 11.6m)
This 50cm extra had a major impact on the total flood damage of the CBD and surrounds.
How flood warnings and evacuations are managed
The downpour prior to the flood in the Tweed, Brunswick and Brisbane catchments was cited by Commander Superintendent Greg Martin, of the Richmond Local Area Command, as a critical contributor to the wrath of last week's destructive weather.
"(The previous rain) was a significant factor in all of this and why we've had the flood we've had," Commander Supt Martin said.
Commander Supt Martin is also the local emergency operations controller for the region, that means he coordinated all relevant agencies for emergencies, such as the recent floods.
He said the emergency operations centre was formed on Thursday afternoon where natural disaster management was rolled out 24 hours a day until Monday afternoon.
At 4.30pm Thursday, the SES issued the first flood evacuation order for North and South Lismore as well as the CBD and the first evacuation text message sent about 5.40pm.
Multiple warnings for residents to evacuate 'low-lying areas' of Lismore, Kyogle and parts of the Tweed Valley including Murwillumbah and Tumbulgum were also issued prior to the levee over-topping on Friday morning.
NSW SES warnings and orders crafted to a state-wide template and text messages are sent using a national emergency alert system.
Commander Supt Martin was confident emergency services provided clear and timely warnings flood-affected areas to prepare and evacuate.
"I am satisfied the emergency agencies did what they could within reasonable constraints bearing in mind the enormity of the matter we were faced with to warn people," he said.
MANY people were simple caught unawares by the speed of the flood. Magellan St resident Victoria Mathews said she rang the police and SES six times on Thursday afternoon and evening to ask if she should evacuate. She was told to stay put. The next morning floodwaters gushed into her home and she had to be rescued by boat, handing her screaming toddler grandkids to SES volunteers.
Said her peak on Friday morning was probably a "metre and a half" higher than what she estimated based on the predicted 11m peak on Thursday afternoon.
East Lismore resident Kate Olivieri and her husband left on Thursday night, but were never subject to a formal evacuation order - even though their low set Molesworth St home is a stone's throw south of the CBD. It ended up in over a metre of water.
But severe weather expert Michael Bath said the levee actually gave people longer to evacuate. But ironically, this may have added to the complacency.
The Lismore basin took 12 hours to fill, and didn't level out until about 5pm on Friday. It was at least six hours behind the peak of the river.
Without the levee, the flooding would have filled up the basin much faster.
Mr Bath said this was the first flood to go over the 2005 levee, so perhaps "people almost couldn't believe it could go over".
In previous close calls in 2009 and 2005, the warnings predicted an 11m flood but it never got there.
SHARED local knowledge helped save The Bircher Bar's stock and equipment before torrents of water nearly consumed the Woodlark St cafe.
Owner Darcy Ogdon-Nolan swung into action on Thursday about 5pm on the recommendation of another business owner, who told him: "the levee is going to break we really need to do this."
Mr Ogdon-Nolan said many in the CBD weren't aware of the ferocity of the rains to come.
"Before that ourselves and a lot of other businesses were just expecting heavy rain but you know it sort of came through last minute that we had to lift everything," he said.
Lismore Mayor Isaac Smith said the levee coupled with the rapid acceleration of the rainfall may have led to delays in flood preparation.
"I think having a levee that has kept floods out for more than a decade has made some complacent and certainly lots of people were caught unaware,"
The warnings rang loud and clear for others like Horn's Gas Services owner, Hayley Brown.
She said her team "busted their backsides" to move heavy stoves and fridges about 1.1m off the ground but it was worth the hard work.
Supt Martin said police and other agencies saw the complacency of others first hand.
"No, we've been through this all before we'll be right" was the response Supt Martin said emergency services received from some residents during door knocking efforts to evacuate those in danger.
In his critical address to media late Thursday night, Supt Martin tried to urge residents "no one was crying wolf" about the severity of the floodwater to consume the city.
He said the weather warnings and predictions in the lead up to the flood "proved true" and that it is becoming clear who did and did not heed the warnings.
"People know this is a flood town when they come here, there's plenty of history of it," Supt Martin said.
"As far as the warnings go, I think it comes back to complacency."
Wednesday, March 29: Ex-Tropical Cyclone Debbie moves into Northern NSW.
Thursday March 30, 12.39pm: Initial Moderate Flood Warning issued for Wilsons River - expected to exceed 7.2m early Friday.
Thursday March 30, 4pm: SES issue major Flood Warning for the Wilsons River - possibly reaching 11m Friday morning.
Thursday March 30, 4.30pm: SES again issue major Flood Warning for the Wilsons River, with around 11m peak expected.
Thursday March 30, approx. 5.40pm: First SMS evacuation order issued for people in Lismore CBD, North and South Lismore.
Thursday March 30, 8.15pm: Major Flood Warning issued for the Wilsons River at Lismore.
Evacuation order issued for low lying areas in Lismore CBD, North Lismore and South Lismore.
Thursday March 30, 9.44pm: Major Flood Warning issued for the Wilsons River at Lismore, a 11.5m peak forecast.
Thursday March 30, 11.30pm: Immediate Flood Evacuation Order for Lismore CBD, and North and South Lismore.
Sirens to sound when levee overtopped.
Friday March 31, 1.36am: Second SMS evacuation order issued for people in Lismore CBD, North and South Lismore.
Friday March 31, 3.10am: Levee breached.
Friday March 31, 11am: Wilsons River peaked at 11.59m.
Friday March 31, 6pm: Water level in Lismore CBD peaked at 11.34m.