By Michael Scott Hill
The 2016-2017 fire season in Australia has been relatively quiet overall with a few periods of increased initial attack activity, like this weekend in mid-February 2017 (see aerial photo). Flying in the rear of a Bell 412 helicopter across New South Wales’ rugged, rolling Blue Mountains with my small RART (Rapid Area Response Team), we are on our way to another fire. This is to be our big weekend chasing fires for this season.
The weather pattern across Australia this summer was basically one of cyclic rainfall broken by several consecutive periods of uncharacteristic extreme heat, until the rains came to cool the land once again. Three heatwaves occurred over the summer, which saw the highest monthly average temperatures on record for Sydney, New South Wales (NSW) and Brisbane, Queensland (QL) and the highest daytime temperatures on record for Canberra, Australian Capital Territory (ACT).
The summer in coastal Sydney ended up with 10 days of above 36 degree Celsius (96 F) as measured from the Observatory Hill in downtown Sydney, breaking weather records that stretch back to the early 1800s. These abnormal high temperatures spikes were carried to the normally cooler eastern areas of New South Wales, across from the hotter desert areas, by a repeating series of weather cycles blowing in a circular motion across the whole southern region of the continent from the west to the east coasts.
Australia’s Bureau of Meteorology stated that, “During these heatwaves, daily maximum temperatures across south-east Australia exceeded 40 degrees Celsius over very large areas and were typically 8 to 12 Celsius above the January and February averages. The highest temperatures recorded during this period were 48.2 Celsius at Tarcoola, SA (South Australia), followed by 47.9 Celsius at Walgett, NSW; these are new February high temperature records at both these sites. While the January 1939 south-east Australian heatwave remains one of the most significant in recorded history, the frequency of such intense large-scale heatwaves has increased across spring, summer and autumn, and especially over the last 20 years.”
Australian Bureau of Meteorology data also shows a pattern in the interior that extended beyond the heatwaves. Behind the rugged Blue Mountains (which shield the cooler Sydney’s coastal basin from its more arid western interior), roughly one third of the state of New South Wales experienced temperatures of 35 degrees Celsius or above for 50 or more days. Such sustained extreme summer temperatures have not been experienced across this region since the summer of 1938 to 1939.
The 2016-2017 summer’s cycle of returning heat spikes peaked during the weekend of the 11th and 12th of February when 120 bushfires took light across the state of New South Wales and over 2,500 firefighters responded to these fires. Two of these blazes were destined to become famous on the national scale — the Kains Flat Fire and the Sir Ivan Fire. Both of these fires were located in the central eastern region of NSW on the backside of Australia’s Great Dividing Range in an area of rolling hills and plains.
Of these two, the Sir Ivan Fire proved to be the most destructive. This fire covered 54,000 hectares with an active fire edge of around 200km which, by the time it was controlled, had destroyed 34 homes, a church, community hall and 120 outbuildings, and damaged six other homes and 30 outbuildings, plus led to huge livestock losses in cattle and sheep.
The small community of Uarbry was completely devastated by the Sir Ivan Fire, and its loses are included in the list above. Across the weekend, two serious injuries were sustained by firefighters; one firefighter was burned on hands and face and the other received a very serious laceration to the hand.
A week later, a series of thunderstorms moving south across the state of New South Wales ignited more than 100 bushfires, which were initial attacked by truck and aircraft based fire crews. This series of fires grew individually to various sizes across the predominantly eucalyptus forest, bushland and grasses, until either rain from the passing storms, or responding emergency personal like us were able to get them under control.
From our group of fires we responded to, the most high profile fire from this late summer storm event started after lightning hit an area of heat-cured grassland in the Australian Capital Territory (ACT).
The grass fire then moved swiftly across the landscape burning sparsely populated, mostly grazing country, 10km east of the community of Queanbeyan on the border of NSW & ACT. This grass fire was called the Carwoola Fire, and before its flames had gone out, it had covered 3500 hectares, led to more livestock loses, and had consumed 11 homes, 45 outbuildings, and damaged 40 others. Sustained firefighting efforts from ground and aerial resources however were credited with saving 56 homes. Sadly in the process, there was a serious injury on the fire, when a firefighter aged in his 40s, suffered pelvic injuries and burns.
Extreme weather events such as these abnormal temperature spikes experienced during the Australian summer could be a rarely reoccurring weather pattern, or it could be the sign of more extreme fire conditions in store for the rest of us who also reside in other fire prone locations across the globe.
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Michael Scott Hill, a contributing editor for Wildfire Magazine, manages fire and aviation with a global perspective from a home base in Virginia (USA).
RELATED – IJWF Research (IAWF membership log-in required)
Variability and drivers of extreme fire weather in fire-prone areas of south-eastern Australia. Sarah Harris, Graham Mills and Timothy Brown.
We identify the most extreme fire weather days based on McArthur’s Forest Fire Danger Index (FFDI) for 24 sites across south-eastern Australia for potential use in fire risk planning. The extent and variability of these highest FFDI days are analysed by the contributions of temperature, relative humidity, wind speed, wind direction and drought indices.
Abstract | http://www.publish.csiro.au/WF/WF16118?jid=WFv26n3&xhtml=F2985ECC-67C6-47C1-988B-3692C049CCF7
PDF (1.8 MB) | http://www.publish.csiro.au/WF/pdf/WF16118?jid=WFv26n3&xhtml=F2985ECC-67C6-47C1-988B-3692C049CCF7
