Australia Weather News

Long grass, which has grown quickly over spring, poses a fire risk for Canberra. - ABC

After years of drought followed by devastating bushfires in and around the ACT, authorities are warning Canberrans to prepare for the unexpected this summer.

The Bureau of Meteorology has declared a La Niña weather event, a phenomenon linked with cooler surface temperatures in the central and eastern tropical Pacific Ocean.

It is also linked with increased rain, plenty of which is predicted to fall in the capital.

ACT Emergency Services Commissioner Georgeina Whelan said her agency was expecting an increase in severe storms.

"What we are at high risk of here in the ACT is flash flooding, so that massive downpour not too dissimilar to what we experienced in February 2018," she said.

That was when a sudden deluge flooded Canberra's inner-northern suburbs, which left some residents temporarily homeless.

Roads in Lyneham, Dickson, O'Connor and Turner were rendered inaccessible and a long stretch of Northbourne Avenue was closed off.

But flash flooding is not the only event that could affect the ACT.

"We could also see some hail, which we hope will be nothing like the extent we experienced last year," Ms Whelan said.

NSW authorities also wary of La Niña effects

Across the New South Wales border, Queanbeyan residents remember the destruction caused by past La Niña systems.

Queanbeyan-Palerang Regional Council Mayor Tim Overall said the last substantial event was in the summer of 2010-11, when the border town suffered significant flooding.

Rising water levels inundated parks and submerged the local cemetery and the Riverside Plaza's car park, causing a mess in the CBD.

Long-time Queanbeyan resident John Britton said the disaster had lingering consequences.

"It affected our work and people mentally," he said.

"The underground car park at Riverside Plaza was underwater — it was just terrible."

Kerry Orchard, who works at the Queanbeyan Riverside Caravan Park, said a flood management plan had been put in place for this summer.

That plan is simple — leave at the first sign of flooding.

"Everything is now mobile so we can pick it up and go, except for the amenities block," Mr Orchard said.

Upstream of the town, Googong Dam is nearly full — and when it fills, it will overflow into Queanbeyan River.

But water supplier Icon Water said there was no point releasing water now to minimise future flooding risks.

"Googong Dam is not a flood mitigation dam — it is a water-storage dam," Icon managing director Ray Hezkial said.

"The value of keeping water in the dam, particularly as we have seen with a volatile climate, is actually of higher value and a higher economic cost than any damage done downstream."

Grassfires another risk for Canberra and Queanbeyan

Above-average rainfall throughout spring has spurred extraordinary grass growth across the region, especially at suburban fringes.

Commissioner Whelan said this increased the risk of late-summer bushfires if a heatwave was to hit the area.

"The ground will dry very quickly and the grass will cure very quickly," she said.

"Maintenance of our environment and our surrounds is going to be very important for us.

"Absolutely everything is possible. Everything is on the table for us here in the ACT."

The same can be said for the Queanbeyan-Palerang area, of which a fifth was burnt during last summer's bushfire crisis.

"The issue is the threat of grassfires more than the national parks' heavy wooded areas," Cr Overall said.

"So [the concern is] grassfires with above-average rains and the high-level growth rate for grassed areas — but those are more easily containable."