Parts of Victoria received more rain in 15 minutes than in the first four months of the year and a tornado-like event flattened a lakeside caravan park as storms swept western and central regions.
Mildura's total rainfall from January 1 to the start of May was 10.4 millimetres. In the 14 minutes after 9.15am on Thursday, 15.6mm poured down on the river town.
Stawell received the heaviest falls, with 68.6mm of rain. It was more than double the 30.2mm of rain the northwestern town had received since January, in what was its driest start to the year since 1996.
The wild weather wreaked havoc in parts, with meteorologists trying to determine if a severe storm which flattened a caravan park in the southwest was a tornado.
Cabins were blown over and boats tossed around when the storm hit Lake Purrumbete Holiday Park about 10.30pm on Wednesday.
Camperdown SES controller Colin Brian described the damage as the worst he had seen in more than 25 years.
"Some of the cabins are just floors and a couple of walls now," he said.
"It was like a mini-tornado went through."
Camperdown police Senior Sergeant Bill Caldow estimated the damage at about $1 million and said it was concentrated on a small area around the caravan park.
Werribee grandmother Wendy Gerring said she was devastated to learn her family's new holiday cabin had been destroyed.
"The first wall that went down, I've no idea where that is," she said.
"I don't know where the roof is."
She and her daughter had the cabin built about four years ago for $26,000, before furnishing it and adding a kitchen, carpet, air conditioner.
While other cabins in the street also lost roofs and walls, some nearby streets appeared untouched.
"This tornado, if that's what it was, just went down the street where our cabin is," she said.
Senior forecaster Rod Dickson said the Bureau of Meteorology was looking into the storm, adding tornadoes were "more common than people think".
Much of western Victoria received between 25mm and 40mm, while areas to the north of Melbourne also received heavy falls.
In the capital, totals were generally under 10mm, with up to 15mm in southeastern suburbs.
Duty forecaster Miriam Bradbury said rain would likely ramp up overnight.
"We're forecasting some pretty high totals, between 30mm to 70mm for parts of northeast, with isolated falls of 100mm, mainly around the peaks."
HIGHEST RAINFALL TOTALS TO 8AM THURSDAY
- 68mm at Stawell
- 53mm at Westmere
- 49mm at Mt Wombat
- 45mm at Mt Hope
- 43mm at Gerangamete
Australian Associated Press