Bushfires: heavy rain to bring relief but also threat of floods, landslides

Heavy rainfall will bring a reprieve for firefighters, but also the threat of floods and landslides.

Heavy rain falls at Melbourne Park on Wednesday. Picture: AAP

Heavy rainfall predicted across Australia’s southeast over the next few days will bring a reprieve for firefighters but also the possibility of flash flooding and landslides to bushfire-affected areas.

A severe thunderstorm hit Melbourne and the Port Phillip Bay area on Wednesday night, with St Albans, in the city’s northwest, receiving a month’s worth of rain in 30 minutes.

The rain, which sparked more than 70 emergency services calls due to flooding, was described as a reprieve from months of extreme bushfire conditions that have claimed 27 lives.

Victorian State Emergency Service state agency commander David Baker said the storms prompted hundreds of requests for help across the day.

“We’ve had about 140 jobs relating to trees coming down, 110 relating to building damage and 110 relating to floods causing damage,” he told The Australian.

“We’ve been coping with it well despite some of our crews being deployed at the fire grounds in East Gippsland.”

Mr Baker said the floods should disappear as the storm system moved away from Melbourne in the early hours of the morning.

“We’ve had no reports of people needing to evacuate ... and the storms should leave Melbourne and head over to the fire grounds early in the morning.”

Victorian man David Moresi has been added to the national toll following­ his death working on the fires in East Gippsland in November. Mr Moresi, 69, had been contracted to help containment lines near Gelantipy, when his vehicle rolled and he died at the scene.

His death takes the toll of ­Vic­torians who died fighting the fires to five. Victorian Emergency Management Commissioner Andrew Crisp said Mr Moresi had been working to keep the community safe.

While air quality in Melbourne had returned to “good” levels by Wednesday night after two days of hazardous conditions, smoke is expected to return at the weekend and to impact the state for months.

Gippsland-based fire incident controller Peter West said on Wednesday the 20-30mm of rain forecast in the area over coming days would provide some relief from fires as well as time to look at building containment lines.

“However, it will only be respite­,” he warned. “The ground will dry up again and we will see those fire conditions return.”

In NSW, up to 50mm of rain is predicted to fall over active fires in the southeast as the cold front moves from Victoria on Thursday.

Rural Fire Service NSW Commissioner Shane Fitzsimmons described­ heavy downpours as a “double-edged sword”, especially if they caused flash flooding and landslides, as firefighters battle more than 100 blazes in the state.

The Bureau of Meteorology is predicting widespread thunderstorms and rainfall for most of the state, except the very far west, from Thursday and into the weekend. “Thursday will be the wettest day for the southeast corner, where a lot of the fires are really still active,” BoM forecaster Olenka Duma said.

Ms Duma said areas of the southeast fire zone could receive 30-50mm across four days from Thursday, while parts of the northeast of the state could see up to 80mm.

Meanwhile, BoM senior met­eo­r­ologist Kevin Parkyn also warnedthe predicted high rainfall in a short period of time could resul­t in landslides. “We’ve got reduced­ vegetation cover. There’s high concentrations of ash, very vulnerable landscape when it comes to short bursts of heavy rainfall, which could see very quickly mudslides developing.”

The fire-ravaged town of Corryon­g in Victoria’s far northeast is forecast to receive up to 15mm of rain on Thursday.

The BoM also forecast a 70 per cent chance of rain in Mallacoota, East Gippsland, on Thursday and Friday, although with falls potent­ially only up to 5mm. Mallacoota continues to be surrounded by fire and its roads remain blocked.