There were up to 2,000 lightning strikes an hour in a series of storms that swept across Victoria this morning.
There was flash flooding, fallen trees and scores of cancellations on the trains.
Lightning is believed to have started a house fire at Berwick, in Melbourne's south-eastern suburbs around 9:30am (AEDT).
The house in Adelong Court suffered significant damage from the fire that started in the roof and spread to the rear of the property.
Lightning is also believed to have damaged a house at Thornbury in Melbourne's northern suburbs, just before 10:00am.
Peter Egan, from the Metropolitan Fire Brigade (MFB) says it sounded like an explosion when the lightning strike tore the tile roof off.
He says the people inside at the time said it was terrifying.
"At the time there were three occupants in the house, a baby asleep upstairs and a husband and wife," he said.
"They've got the baby out and evacuated the property and crawled to the gate."
All rail services are operational again after lightning also damaged signalling equipment right across the train network.
Across the state, the SES has had more than 90 calls for help, from Knox, Oakleigh and Nunawading.
There was flash flooding at Centre Road, in Clayton, at St Kilda Junction, at Alexandra Avenue, at Como Park and the Calder Highway at Gisborne.
Bureau of Meteorology duty forecaster Chris Godfrey says there has been about 25 millimetres of rain in Melbourne and the suburbs before the storms clear to the east of the state this afternoon.
"At this stage we are looking at the weather starting to improve as the day goes on," he said.
"In Melbourne at least, there is still the likelihood of thunderstorms until around 1:00pm (AEDT) then we should see the skies clearing."
© ABC 2012
12:46 EDT This summer has been in the top three hottest summers on record for much of WA.