The State Emergency Service says Victoria's devastating 2010-11 floods may be repeated, during an intense burst of rain that's about to hit the state.
Victoria's 2010/11 floods were estimated to have caused $1.3 billion worth of damage.
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The Bureau of Meteorology is predicting falls of up to 100 millimetres of rain in the coming days for some parts of the state.
The BoM said a cold front and low-pressure system, would bring widespread heavy rainfall from Wednesday for Victoria, northern Tasmania, southern New South Wales and far eastern South Australia.
Bureau forecaster Kevin Parkyn said there was a significant rain event "on Victoria's doorstep".
"What I am most concerned about is the intensity of the rain that will peak on the Thursday," Mr Parkyn told a briefing at the State Control Centre.
"We have a short term flash flood risk, as a result of that rainfall intensity, and then a longer term, riverine flooding risk, as it will take a while for some of those waters to find their way down river systems"
"We've seen tropical moisture build over the top end of Australia for some time now, that's courtesy of the negative Indian Ocean Dipole, and a third successive year of La Nina."
State Emergency Services chief operations officer Tim Wiebusch has warned Victorians to prepare for flash and riverine flooding.
"All Victorians now need to prepare for flooding that is likely to occur for another six to eight weeks, on and off, as we continue to see these events roll through," Mr Wiebusch said.
"The peaks might occur in the first three to four days, from Friday through to Monday, but we could see moderate to minor flooding ensuing on a number of those large catchments for another seven to 10 days after that.
"The indications are if we see the upper-end rainfall, we could see some flood conditions - particularly in the west of the state - that could be aligned to what we saw in 2010-11."
In the north-east of Victoria conditions could be similar to 2016.
"We are talking about isolation, we will see roads cut, we will see parts of communities that may be inundated with floodwater," he said.
All the river systems in the north fed into the Murray River, adding to inflows from NSW.
"We are likely to see the Murray River in flood for many, many weeks," he said.
Mr Wiebusch said full dams were already spilling.
"A lot of our water storages in Victoria have spillways, rather than gated releases, so that does mean when they do reach capacity whatever is coming in is going out," he said.
"Once those reservoirs start to fill and spill, that is going to exacerbate problems on some of those systems, but that is built into the modelling."
In recent days, the Dartmouth Dam had spilled for the first time in 26 years, and Lake Eildon was about to reach a point where it was about to go over for the first time in 28 years.
The Thomson Dam, in Gippsland, was also set to spill, after reaching 98pc capacity.
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SES preparations
SES vehicles had been moved to areas where they would be most needed, he said.
"Communities will have an understanding of where some of those hotspots have been, in the past," Mr Wiebusch said.
He said residents should listen out for warnings.
"Across the state, over these coming days, all of our river systems north of the Dividing Range are at risk," he said.
"Communities around the Wimmera, Avoca, Loddon, Campaspe, the Broken, King, Ovens and the Kiewa and also parts of the Murray rivers are at risk," he said.
South of the Divide, there was concern where the Moorabool and Barwon Rivers converged.
There was only expected to be minor flooding in Gippsland.
Residents living in flood prone areas would need about 25 sandbags, to block the front and back doors, drains and toilets.
"They can get those sandbags from local hardware stores and councils and we will set up collection points, in coming days," Mr Wiebusch said.
Significant flood season
Premier Daniel Andrews said the state was facing a "significant" flood season, this spring.
"There are a couple of hundred generators, out at Laverton, waiting to be forwarded to communities who may lose power," Mr Andrews said.
"There are seven choppers on standby, and more that can be accessed, if we need them.
"They will be forward deployed as well, once we have a clearer picture of where the most significant rainfall event has unfolded."
The government also had Community Containers, containing essential items for flood victims.
"If a community was completely isolated, we can - by road or by air - get to them a generator, satellite phone, basic supplies of water, all those basic essentials that can sustain up to 50 people for five days," he said.
The containers, or caches, would go to residents cut off by flood waters, or damage roads and bridges.
The caches are designed to equip responders and community members with emergency tools including first aid and hygiene essentials, infant supplies, dust masks and respirators, batteries, water, food and cooking supplies, tents, lighting, bedding and equipment needed to set up an emergency base.
The Premier said there were also hundreds and thousands of sandbags, and sand, available.
Andrew Miller
I'm a general reporter with Stock & Land, with a special interest in irrigation issues. I completed my cadetship, with the Age, in 1980. Over my career, I've worked for ABC radio news (Mt Isa, Qld) and at provincial and suburban newspapers.
I'm a general reporter with Stock & Land, with a special interest in irrigation issues. I completed my cadetship, with the Age, in 1980. Over my career, I've worked for ABC radio news (Mt Isa, Qld) and at provincial and suburban newspapers.
