Horror day looms, warns former south-west CFA volunteer fighting fires

Leigh Dwyer, who was a member of the Toolong Fire Brigade before moving to Ararat, said people whose houses were under threat should leave immediately.

"It's going to be one of the worst days a firefighter can experienced," she said.

"We're well trained but people should just leave if they need to.

"You don't want to be standing in front of what's coming tomorrow."

Wednesday is a day of total fire ban in the south-west.

Ms Dwyer said the horrific conditions made the Pomonal blaze one of the worst she had ever experienced.

"The wind was constantly swirling around - we didn't know where we were going to get hit from," she said.

The strike team the Ararat Fire Brigade member was was part of was unable to join other firefighters at the town hall when an evacuation call was made.

"We had an evacuation call to fall back to the oval, which we couldn't do because we were burnt in," Ms Dwyer said.

"We had to stay put until the front went past."

Ms Dwyer said visibility levels had been close to zero at some points while fighting the blaze.

Thankfully, the team was able to save the home.

Ms Dwyer has been a volunteer for about two decades and knows she is preparing for one of the toughest days on Wednesday.

When asked what motivates her to volunteer for the CFA, Ms Dwyer said the answer was simple: "to help people".

Tens of thousands of Victorians are on alert for bushfire danger and 100 schools shut as Victoria braces for potentially catastrophic weather conditions.

The Wimmera region in the state's west faces a catastrophic fire danger rating on Wednesday, with firefighters coming from interstate to help protect the area.

Five other regions are extreme, with a total fire ban declared for all catastrophic and extreme regions.

Some 30,000 people in communities around two bushfires in the state's west will be sent alerts on Tuesday advising them of the danger and asking them to heed warnings to leave early.

Authorities have created a map of where the fire could potentially go, including towns such as Beaufort, Elmhurst, Amphitheatre, Lexton Learmonth and Clunes.

"Fire, spot fires and ember attack are quite possible in these areas, these could result in loss of homes, closure of roads and isolating communities," Emergency Management Commissioner Rick Nugent said.

Country Fire Authority chief Jason Heffernan said the peak fire threat was expected from noon on Wednesday until about midnight.

He urged people planning to leave the area to get out on Tuesday night or early on Wednesday.

"I would not leave it any later than lunchtime because those weather conditions will become quite nasty from 12pm onwards," he said.

Victorian premier Jacinta Allan said close to 100 school and early childhood facilities would shut on Wednesday while vulnerable people in aged care and hospitals have been taken away from the danger.

The Mallee region was slated to reach mid-40C and get winds of up to 45km/h on Wednesday while other parts of the state were also expected to creep into the 40Cs.

The threat comes as a watch and act alert remains for the wild Bayindeen fire, north-west of Ballarat, which had burned through more than 21,300 hectares as of Tuesday morning.

So far six homes and 10 other buildings have been lost to the fire.

Crews are coming from NSW to help the hundreds of firefighters on the ground who have been battling the blaze since it sparked on Thursday.