Hot, windy conditions are set to sweep the Australian state of Victoria today, with authorities warning any fires that start will be uncontrollable and unpredictable.
Emergency Services Minister Lisa Neville said it is "really, really disappointing" people have already broken a statewide fire ban, after firefighters responded to three campfires in rural Victoria by 8am (local time).
"There are two strong messages: one a total fire ban, no campfires at all, but secondly, if you are leaving your camp area, absolutely make sure that campfire has been put out appropriately," she said.
Mildura, Swan Hill, Kerang and Echuca in the state's northwest are tipped to hit 46degC, while Bendigo heads to a top of 45degC and Melbourne is forecast to reach 42degC.
A cool change will bring welcome relief for some areas later in the day, with forecasters predicting a temperature drop of almost 20degC in as few as 15 minutes.
However, it may bring wind gusts up to 100km/h for up to two hours, with the potential to exacerbate fires.
Thunderstorms are also expected in parts of central and eastern Victoria in the late afternoon, with the possibility of dry lightning strikes posing a fire risk.
Temperatures rose rapidly on Friday morning, hitting 40degC in parts of the northwest by 10.30am, but are set to drop suddenly in coastal parts including Melbourne by about 4pm (local time).
"As the change moves through, we could see it pretty much dropping from our maximum temperature of about 42degC for Melbourne down to around the mid-20s in only a matter of 15 minutes to maybe half an hour," Tom Delamotte, of the Bureau of Meteorology, said.
CFA deputy chief officer Garry Cook says it will be a challenging day ahead and people need to stay alert to conditions.
"The potential for fires to get up and run and cause significant damage in a short period of time today, with the conditions we've got, is real and people need to be informed and stay informed," he told 3AW.
People are urged to stay indoors, stay hydrated and avoid unnecessary activity and travel.
"Don't wait until it's too late. Have a plan now as to what you're going to do. Let's get through the day unscathed," Mr Cook said.
Victorian SES state controller Tim Wiebusch said extreme and severe fire danger exists in most of the state, particularly the north and west, and warned any blazes could become "uncontrollable and unpredictable".
"As that wind change starts to cross the state from later this morning and into this afternoon, that will be the most vulnerable time in various parts of the state," he told ABC.
"Particularly if fires are already in the landscape, they'll actually change direction. That's where people will need to be alert to their conditions."
Health authorities warn the conditions could prove fatal, while the Environment Protection Authority (EPA) says the winds could raise dust and reduce air quality in Melbourne and Geelong.
"This should clear out with the wind change forecast for the late afternoon, but we encourage people to visit the AirWatch website for real-time air quality information," air quality scientist Gavin Fisher said.
