Fires and floods, fires and floods: Australia’s summer of extremes

Australia has endured an extreme summer of fires and floods – followed by more bushfires, and more floods – as the country’s arid red centre braces for record flooding and south-eastern states brace for increased bushfire risks between March and May.

Flash flooding hit Sydney overnight on Thursday, and some regions in the red centre recorded more rain in 24 hours than would usually be recorded in a year.

Weatherzone meteorologist Ben Domensino said 169 millimetres was recorded at Nappa Merrie in central west Queensland in the 24 hours to 9am on Wednesday.

“This is exceptionally heavy rain for these parts of Australia,” he said.

“For example, Nappa Merrie is in a part of Queensland that usually receives about 100 to 200 millimetres of rain in an average year. On Tuesday night this week, they picked up 97 millimetres in just six hours.”

More than 100 millimetres of rain fell in Sydney’s CBD and south-west on Thursday night, triggering 42 rescues and a dozen evacuations as homes and businesses were inundated.

Bureau of Meteorology senior climatologist Dr Simon Grainger said this summer had been marked by severe heatwaves in December and January in NSW, Victoria, Tasmania, South Australia, and much of Western Australia. More than 60 sites across the country recorded their highest ever temperatures in the last week of January.

“But in the north of Australia, we’ve seen below-average temperatures across much of northern western Queensland and into the Northern Territory, and that’s been a region this summer that’s had very much above-average rainfall – that’s rainfall in the top 10 per cent of all years since 1900,” Grainger said.

Australia’s summer has been marked by repeated floods, and bushfires that turned deadly. In Victoria, more than 400,000 hectares was destroyed, including about 120,000 hectares in the Walwa-Mount Lawson state park.

Communities along the Great Ocean Road were threatened by bushfires, then flash flooding, and then bushfires again, while in Western Australia an estimated 2500 lightning strikes sparked 20 bushfires.

The Bureau of Meteorology issued a long-range forecast for autumn on Thursday night, predicting unusually dry conditions for southern Australia, and a wetter than usual autumn in the Northern Territory and the Cape York Peninsula.

Autumn will bring increased risks of bushfires across most of Victoria, including Melbourne. Only the state’s east and north-west are forecast to face average fire risks.

The Australasian Fire and Emergency Service Authorities Council, the body comprising national fire chiefs and agencies, issued a statement on Thursday saying that long-term rainfall deficiencies continued to persist across Victoria, parts of NSW, and agricultural areas in South Australia.

In NSW, parts of the southern, central and eastern areas in the state are forecast to be at higher risk of bushfires over the next three months. In WA, there will be increased bushfire risks between Margaret River and Albany, and the region around Esperance.

Above-average daytime and night-time temperatures are expected from March to May for most of Australia, while rainfall is expected to be lower than average for southern parts of Australia.

“The increased bushfire risk potential is driven in part by long-term drought throughout Victoria and SA, along with increased dryness in NSW and persistent soil moisture deficits in parts of WA, the south-east mainland and Tasmania,” the chiefs said in a statement.

In the arid centre of Australia, however, roads have closed in a number of towns as intense rainfall creates widespread flash and riverine flooding.

Flood watches are in place for parts of NSW, South Australia, Queensland and the Northern Territory.

Across the vast Kati Thanda-Lake Eyre, which is Australia’s largest salt lake and which has filled to capacity only three times in the past 160 years, flooding is taking place for the second time in two years.

Adjunct professor of environmental geography Steve Turton suggested in The Conversation the lake could top its 1974 depth record of six metres.

Arid Air co-owner Phil van Wegen, who runs aerial tours of the region with his wife Maria, doesn’t doubt it.

“It’ll be pretty spectacular, this volume of water – it’s unprecedented,” said van Wegen. “The records are getting busted everywhere.”

The couple have been grounded by heavy rains in Marree, driven by a persistent low pressure system that hasn’t budged from Australia’s centre for days. Locals have been sandbagging the town, and preparing for homes to be flooded.

“It’s definitely going to be a big flood event, bigger than last year,” van Wegen said.

“They’re talking another big rain event in early March. So it’ll be well into July, August, before we see exactly what the total amount is.”

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