Some drivers reported hour-long delays as they were stuck in traffic.

Two lanes were blocked outbound on the West Gate Freeway at Williamstown Rd due to flooding.

The speed limit was set to 40km/h while commuters were urged to drive carefully and obey overhead signals.

Two flights were diverted to Avalon from Melbourne Airport.

A Rex flight from Sydney, and a Virgin flight from the Gold Coast were forced to change course.

The wild conditions resulted in about 5000 people losing power across Melbourne, according to electricity retailer AusNet.

The majority of the outages occurred in Pakenham, in the city’s south west, where over 3000 people lost power.

Almost 900 people lost power in Leongatha in South Gippsland, while nearly 700 people suffered power outages in Greensborough in Melbourne’s northeast.

There were more than 230 weather-related calls for assistance across Melbourne as the wild storms damaged buildings and closed roads.

The State Emergency Service said the majority of calls related to building damage, flood events and fallen trees.

The worst-affected suburbs were in the city’s west and included Sunbury, Essendon and Maribyrnong.

Meanwhile, some motorists were forced to detour after Dudley St in West Melbourne was closed in both directions due to flash flooding under the rail bridge.

And drivers are being warned to expect significant delays after a spate of car crashes across the city.

Department of Transport spokesman Andrew Crook said minor collisions in the city had helped cause congestion, along with commuters driving slower due to the weather conditions.

Cancellations have slowed travel on the Cranbourne, Pakenham and Sunbury rail lines, while minor and major delays affect several other routes.

A tram derailed in Maribyrnong about 4.45pm because of the wild weather, but traffic has not been impacted.

Buses replaced trams on routes 57 and 82.

The SES has urged Victorians to be extra careful this season as the state enters its second La Nina summer.

“With catchments wetter and water storages fuller than in 2020 — along with our experience last year — we know Victorians are at increased risk from flooding,” chief operations officer Tim Wiebusch said.

“Please don’t drive through floodwater, it may be the last decision you make.

“Even if you think you know the road, you can’t see the extent to which it has been washed away. It only takes 15cm of floodwater to cause a car to lose traction, which sadly is how most people lose their lives during a flood.”

The weather bureau updated its severe weather warning to include damaging winds, large hailstones and heavy rainfall as slow moving storms made their way across the city.

Melbourne Airport recorded a gust of 106km/h while Fawkner Beacon saw 96km/h winds on Wednesday afternoon.

The bureau warned heavy rainfall could lead to flash flooding.

The SES advised motorists to pull over if conditions were dangerous and avoid travel if possible.

“The Bureau of Meteorology warns that, at 3.55pm, severe thunderstorms were detected on the weather radar near Caulfield, Footscray, Melbourne City, Werribee and waters off Portarlington.

“These thunderstorms are moving towards the east.

“They are forecast to affect Essendon, Kew and St Albans by 4.25pm and Glen Waverley, Melbourne Airport and Preston by 4.55pm.

“Damaging winds, large hailstones and heavy rainfall that may lead to flash flooding are likely.”

Anyone out in Port Phillip Bay will also be impacted by the slow-moving storm and a minor flood warning is in place for both the Snowy and Murray River.

THUNDERSTORM ASTHMA ALERT

Meanwhile, on Wednesday afternoon, the health department also issued an emergency warning, saying anyone with asthma or hay fever should be prepared for thunderstorm asthma.

“Due to unexpected storm activity and high pollen count there is an elevated risk to people with asthma and hay fever,” a spokesman said.

They urged people to stay inside during the storms, avoid the winds beforehand and carry their asthma medication.

People experiencing mild asthma symptoms should contact nurse on call on 1300 60 60 24 for medical advice.

“If your condition is urgent, not improving or getting worse, call Triple Zero (000),” the spokesman said.

“Call Triple Zero (000) if someone is not breathing.”

WILD WEATHER HITS REGIONAL VICTORIA

Storms are also set to hit parts of regional Victoria.

In addition to regional areas captured by the warning for the Greater Melbourne storm, parts of the Central, Mallee, North Central and Wimmera forecast districts will be hit by damaging winds, large hailstones and heavy rainfall.

The State Control Centre has also declared a Total Fire Ban in the Mallee for all of Thursday.