At a time of bushfires in the news – a reminder about facts of Black Saturday 7 Feb 2009 temperatures

The Bureau of Meteorology through the media is prone to quote the 46.4 degrees temperature recorded in central Melbourne on that day – also spruiked as all time Melbourne hot day. Although what exact relevance the temperature in the middle of the huge and growing Melbourne urban heat island (UHI) has to conditions on the fire grounds – I do not know.

It is worth remembering that the maximum temperature at Kilmore Gap on Black Saturday was 42.7 – that is the nearest recording available to where a power line failure ignited the Kilmore fire – which amidst Govt Fire Authorities confusion – birthed the Black Saturday disaster.
It needs saying that there are other constant biases in what the media report from the BoM.
Statements such as “Hobart or Melbourne or Perth had their hottest day ever on a certain date” – quite apart from not warning readers/viewers that the UHI will only drive temperatures higher over time – does not take into account that our long term temperature stations are mainly in cities and towns. There are very few long term stations from rural locations around which people have not congregated over the decades.
Also we have many more weather stations in recent times than say in the 1880′s – so once again here is a bias in the BoM claiming recent “hot day” records and watching for their latest “Holy Grail” – the “overall Australian hottest day”.
Currently the BoM claims the highest daily average maximum temperature, averaged over Australia is 40.2 on 21/12/1972. HTChris Gillham
Earlier data was too sparse to be comparable so of course eventually they will claim that a certain day will be “Australia’s hottest day ever” but there will be no comparable data to check back over our history.

6 comments to At a time of bushfires in the news – a reminder about facts of Black Saturday 7 Feb 2009 temperatures

  • Geoff Sherrington

    Thanks, Warwick, I’ve noted similarly.
    It’s too hard to move from a scale of minutes to a scale of hundreds of millions of years in this climate work. On Feb 7 2009 we were about 50k south of the Kinglake fires and about 15 km east of Melbourne weather station 86071. The wind was from the north where the fires were, so now I’m wondering if the ‘record’ high was slightly affected by air heat from the fires, like a small scale of Dunalley Tasmania the other day which showed a transient of 55 degC. You need minute-by-minute data to interpret that type of event and I don’t have it for the Melbourne 2009 fires. It is of note however that on the evening of the fires, the Tmin was quite low, this affecting Tmean as sent (or is it?) to NOAA.
    I think that it’s going round in smaller and smaller circles looking for occasional records in odd places and times. There is propaganda value for some, but that’s not really my game or yours.

  • Ian George

    The Bureau has not given a max temp for Dunalley for Jan 4th as yet – it will be interesting to see what happens in this case.
    Geoff,
    I was interested in your idea re fire induced temp. I ran the figures for Hobart’s Ellerslie Rd and compared them with Hobart AP.
    1967 Ellerslie Rd 39.3C 1976 40.8C 2012 41.8C
    1967 Airport 39C 1976 37.7C 2012 40.3C

    Both 1967 and 2012 had the bushfire effect. I can’t find anything about fires in 1976 except that there were some 40 fires in Tasmania about that time but no specific mention of them near Hobart. There is a huge discrepancy between the stations in 1976 but little difference when fires were near.

    In Feb, 1851 the temp was 47.2C in Melbourne. With fire covering some 25% of Victoria, it may have well been that temp.

  • Bob in Castlemaine

    Experienced here in central Victoria, even though we escaped local fires, the weather on “Black Saturday” 7 February, 2009 was truly terrifying. The old timers relate similar impressions of “Black Friday” on 13 January, 1939. Fortunately such catastrophic weather events don’t come along too often, but they do go back as far as the very early days of European settlement in Victoria and undoubtedly long before that.

    The extreme heatwave culminated in a day of searing hot wind, Melbourne’s maximum temperature reached 47.2 deg C. Savage bushfires raged throughout Victoria (then part of the colony of New South Wales) burning an estimated 5 million hectares, more than 25% of what was to become the state of Victoria.

    “I afterwards went to live at a lawyer’s in Little Collins Street. I had to look after his horse, and clean the office and mind it while he was away. Mr. Burnley* used to stable his horse with us. He had property there and at Richmond. Burnley is named after him.

    It was while I was here that the fearful day called Black Thursday took place. It could not be forgotten by those who were in it. All business was suspended; shops could not be opened; and everything seemed one mass of glaring fire and smoke. Ashes were falling everywhere, the wind was like the blast from a furnace; and candles had to be burned in the houses to see. Some people thought the Judgement Day had come. I felt very solemn, for I knew I was not fit to stand before His awful presence.

    I started to take my horses to water at the river. I could not see one yard before me, but had to guess my way. Directly I reached the river, the horse that I was on laid down and rolled with me on his back and half drowned me, but I managed to disengage myself. The dust, smoke and ashes were going across the water in one thick cloud, so I could see nothing. I jumped on his back and shut my eyes (for I could not keep them opened) and galloped home. Such was the intense heat that I was dry in ten minutes. I lay down in the stable for some hours, quite exhausted. If I put my head outside I could not bear the heat, I felt that I should be smothered; so I had to stop inside and let things take care of themselves.

    The desolation and distress that was all over the colony is a matter of history. All the bush between Melbourne and St. Kilda was burned, and all the ti-tree scrub along the banks of the Yarra, and all the farms around Melbourne for miles were burned. Many people were coming into town for days after, who had lost everything, cattle, horses and all, and who felt thankful that they had escaped with their lives. Men and women with families, with nothing but what they had on them, and some of that was singed with the fire. There was some lost their lives, and some had to stand in water up to their necks. O the distress was pitiful – none can know it but those who witnessed it.

    *W.B. Burnley, an early purchaser of land in Richmond.”

    “Black Thursday” 6 February 1851, from “Forty Years in the Wilderness” the autobiography of John Chandler, edited by historian Michael Cannon.

    “FATAL AND DESTRUCTIVE BUSH FIRE – Intelligence reached town yesterday morning of a most destructive bush fire that had been raging on the previous day, at the Plenty River. On the station formerly known as Anderson’s Station, between the Plenty River and Diamond Creek, the destruction was very great, and it is stated that a poor woman, wife of a shepherd named McClelland, was, with five children, suffocated in a hut from the smoke of the fire which raged around them, and left no means of escape. The Coroner has been made aware of this fact, and has appointed to-day to hold an inquest on the bodies at the Bridge Inn, Plenty River. Eight or ten farms in the neighbourhood have been entirely destroyed, stacks, buildings, fences, everything; whilst several men are missing, and fears are entertained that they have perished. A possibility, however, exists of their having saved themselves by timely flight.”

    “Black Thursday” 6 February 1851 – from “The Argus” newspaper of 8 February 1851

  • George Bailley

    Warwick

    The answer is in your graphic. Kilmore Gap is about 414m higher than Melbourne Airport. The Dry Adiabatic Lapse rate (DALR) is 1 degree per 100m. Ergo Kilmore Gap should be 4.1 degrees cooler than Melbourne Airport max.

    And it is. Nothing to see here.

    George

  • Geoff Sherrington

    4. George
    Is it as simple as that? I’m not so sure.
    In a static set of conditions, there are figures given for dry and moist adiabatic lapse rates, about 1 deg C per 100m vertical, as you note, for the dry rate.
    However, in a dynamic set of conditions where there is fast air movement up a slope, driven by pressure differentials as wind can be, does the air mass have time to revert to a lower temperature? Should the lapse rate concept be replaced by a different rate, because work is being done to push the air up the hill. This work should eventually report as extra heat.
    As I understand it, the usual lapse rate concept, absent inversions, really relies upon air rising until it reaches a layer of its own temperature (it decreases during the rise). But, no work from an external source is used to make the air rise.
    Is it too simplistic to say that air blown up a slope loses at least some heat by conduction, otherwise it would not show up on a weather station thermometer?
    It’s a fairly important question because of the algorithms used (or not used) in places like the USA when calculating CONUS and global temperatures.
    It’s not as simple as the Ideal Gas Law.

  • George Bailley

    Hi Geoff

    Yes, sadly, it is that simple. It is physics. P V = n R T as you indicate. Time is not a variable.

    Airparcels do not heat as they ascend nor cool as they descend (in absentia of other factors such as evaporation).

    If you want to play an interesting game (?) – pick two closes site – say Perth Airport and Bickly in WA – and compare observations in a well mix situation. There is a 370m difference in height. They should be 3.7 degrees difference in temperature. At 10pm – when I just looked – Perth airport was 24.9, Bickley was 21.4 – a difference of 3.5 degrees. At 10am this morning they were 4 degrees apart.

    George

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