10/01/2020

(AU) BOM Review Shows 2019 Was A Year Of Weather Extremes

ABC Weather - Kate Doyle

The attitude required to get through our hottest and driest year on record. (ABCMyPhoto: Clancy Paine)
From heatwaves and fires to floods and snow, 2019 was a big year of weather.
It wasn't just hot and dry, it smashed the records.
Australia's average maximum daytime temperatures really sizzled — last year was 2.09 degrees Celsius above the 1961-to-1990 average, smashing the previous record by half a degree.
Dr Karl Braganza, the Bureau of Meteorology's head of climate monitoring, said it was the first time an annual anomaly had been two degrees above average.
Annual mean temperatures were also the highest on record for the country as a whole, at 1.52C above average.
There has been a clear upward trend in average temperatures over the past century. (Supplied: Bureau of Meteorology)
It was also Australia's driest year on record, with only 277.6 millimetres of rain for the country on average, 40 per cent less than the long-term average.
Dry years are often hot because rain cools things down, but this is the first time a year has been both the hottest and driest on record.
The previous driest year was 1902, at the end of the federation drought and before the official temperature record began.

2019 wasn't all fire
In Melawondi, near Kandanga and Imbil on the Sunshine Coast, residents collected hailstones in buckets. (Supplied: Bobbie Hamilton)
Major flooding from February to April across western Queensland brought relief to some and devastation to many.
It has been estimated 664,000 cattle died when floodwaters covered much of the Channel and Gulf country.
The on-flow ended with the ephemeral Lake Eyre reaching 65 per cent capacity, its fullest since 2011.
Then, dust storm after dust storm swept across the country along with a number of storm storms that caused havoc — from wrecking the vineyards of South Australia's Riverland to pelting down 11-centimetre hail in Queensland's Wide Bay region.
Widespread snowfall in August feels like a lifetime ago. (ABCMyPhoto: Ross Long)
The south-east of the country was even sprinkled with snow at one point, with the AFL's first snow match in Canberra in August.
Doesn't August feel like a lifetime ago?
But yes, the main story of 2019 was the heat and the fires.
The 2019-20 fire season will forever go down in the record books. (ABCMyPhoto: Martin Von Stoll)
January was plagued by heatwaves, making it Australia's hottest month on record.
Fires burned through Tasmania for weeks, resulting in the state's worst fire season since 1967.
There were also major blazes in Victoria and Western Australia early in the year, only for that devastation to be eclipsed by the recent horror fires.
2019's rainfall was below that of even the millennium drought years. (Supplied: Bureau of Meteorology)
Fires have been raging since September.
On December 17 and then 18, Australia surpassed its hottest day on record — the 19th only missed out on the hat-trick by a whisker.
By the end of December, the BOM's report states more than 5 million hectares have been burnt across Australia since July.
"The extensive long-lived fires appear to be the largest in scale in the modern record in New South Wales, while the total area burnt appears to be the largest in a single recorded fire season for eastern Australia," it said.

Yes, climate change is involved
The majority of Australia recorded rainfall well below average during 2019. (Supplied: Bureau of Meteorology)
The main climate drivers this year were the strongest positive Indian Ocean Dipole (IOD) on record, with a strong negative burst of the Southern Annular Mode (SAM) late in the year.
Both contributed to the hot dry conditions, but this natural variability happens on the foundation of rising temperatures and increasing fire danger for Australia, Dr Braganza said.
"We've got very-well-defined and clear trends, underlying the change that we've seen over the past several decades," he said.
"We've seen clear trends in maximum, minimum and average temperatures across Australia.
"We've seen quite clear trends in reducing rainfall across south-west WA and parts of the south-east."
Red regions indicate where fire weather increased between 1978 and 2017. (Supplied: Bureau of Meteorology )
He said the BOM had also seen a clear trend in fire weather, both in terms of longer and more severe fire seasons.
"The fire season has extended by months in some locations, particularly along the south coast and east Gippsland.
"We're getting more fire weather during the season, and the fire weather we're seeing is more severe.
"That's reflected in heatwaves as well in many parts of the continent."

The year that will be
How 2020 will follow is yet to be determined, but that underlying trend is not going away.
The current outlook is for relatively neutral conditions; the positive IOD broke down as the monsoon moved into the Australian region.
But that doesn't mean we are out of the woods.
"We're not seeing an indication of odds favouring a lot of widespread, above-average rainfall, but we are seeing indications of some rainfall starting to come in with the northern monsoon," Dr Braganza said.
"The hope is that they start to cool down parts of the continent over the central and north-west, which tends to assist in cooling temperatures down a little.
"But really, it's been very hot and dry already. It's still the start of January, there is a deal of summer to go."
Rain and cyclones might finally be coming in the north, but the call is to remain vigilant as the traditionally hottest months of summer are still to come.

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