Thousands without power as storms lash Victoria during heatwave

A severe storm has cut power to 500,000 customers as extreme temperatures, strong winds and "thousands of lightning strikes" cause damage to electrical infrastructure.

Residents in Geelong and the Surf Coast, Ballarat, Maryborough and the western suburbs of Melbourne were "hardest hit" as crews worked to restore power.

A Victorian heatwave, that closed 60 schools on February 13, has also caused a "significant power system event" with the state's largest generator tripping and sending electricity prices soaring to $16,600 per megawatt hour.

The Australian Energy Market Operator (AEMO) said it was investigating the cause.

"In Victoria, the Moorabool to Sydenham 500 kilovolt transmission lines tripped, multiple generators disconnected from the grid and some consumers experienced a loss of electricity supply," AEMO said.

Minister for Energy and Resources Lily D'Ambrosio said "AEMO is working hard to restore power".

She said "one unit at Loy Yang A power station has come back online and as a result forced load shedding is no longer required to maintain grid stability".

"The situation remains volatile. I'll continue to provide updates as they become available."

Load shedding is a "planned reduction of electricity to selected areas during extreme events to protect the electricity network from long-term damage and widespread consumer outages," AEMO said.

Residents of Dadswells Bridge, Ledcourt, Roses Gap, Wartook in the Wimmera region are urged to leave immediately after wind picked up around a bushfire in the Grampians National Park.

"There is a bushfire at Grampians National Park, Mt Stapylton that is not yet under control and is travelling in a south-easterly direction," CFA said at 3.20pm on February 13.

"A south westerly wind change in the area will cause the fire to change direction towards Dadswells Bridge and Ledcourt.

"Conditions are now dangerous and unpredictable."

CFA said two bushfires, not yet under control, were being managed by firefighters in the Grampians National Park.

Residents of Bellfield, Bellfield Settlement, Halls Gap, Pomonal and Grampians Junction were also warned to leave the dangerous area as firefighters battled the blaze.

"The bushfire in the Grampians National Park located near Bellfield is travelling in a southerly direction," CFA said.

"Pomonal could be impacted anytime within the next two hours."

A haystack fire is blazing at McNicols Rd, Kalpienung north of Wycheproof in north west Victoria and firefighters were on the scene.

A grassfire is burning at Stockyard Hill, west of Ballarat, "that is not yet under control" and travelling in a north-easterly direction towards Lake Goldsmith.

CFA said five small fires were burning at the NSW border in the Cobram Track area.

Firefighters had contained four of the blazes with mineral earth breaks but warned that high winds, that could make visibility difficult, were expected.

CFA said there was "currently no threat to communities, but you should continue to stay informed and monitor conditions".

Catastrophic Fire conditions were forecast for the Wimmera region, including Horsham and Halls Gap, in Victoria's west, CFA chief officer Jason Heffernan said.

This is the first "catastrophic" fire danger warning for Victoria in five years.

Mildura, Swan Hill and other towns in Mallee have been issued with an extreme fire danger.

High fire danger ratings have been issued for the rest of the Victoria, excluding East Gippsland.

Extremely hot, dry and windy conditions will increase the overall risk of fire across Victoria.

Wind gusts potentially reaching 60 to 80 kilometres per hour are predicted on February 13 with thunderstorms and dry lightning in the afternoon.

Schools in Victoria's north-west closed on February 13 as the heatwave sparked some of the most dangerous grassfire conditions since the Black Summer of 2019.

National parks in the state's west are also closed and power outages are likely, Victoria's Country Fire Authority (CFA) said.

"Around 60 schools and early childhood education and care services in the district will be closed and some surrounding schools in the North West area may be relocated," a Department of Education spokesperson said.

"All impacted schools and services have been notified and families are being advised.

"The health and safety of our children, school students and staff is always our top priority, and we will continue to work closely with emergency services as the situation develops."

School closures will be updated by the Department of Education through their portal.

The department said it has been "advised of school bus service impacts travelling through the Wimmera district, including Balmoral, Casterton, Dimboola, Donald, Edenhope, Great Western, Horsham, Kaniva, Minyip, Murtoa, Nhill, St Arnaud, Stawell, and Warracknabeal".

"Your child's school will be in contact if your school community is affected."

CFA recommends using multiple sources to stay informed: