Bushfires in Australia

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openBrain
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Re: Bushfires in Australia

Post by openBrain »

Guys, how about pinning this topic only in the 'Open Discussion' subforum ? Not that I want to minimize disaster it is, and I'm glad to read jim's minutes. But having it on top of all pages across the FreeCAD forum seems a bit ... "out of scope". ;)
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Re: Bushfires in Australia

Post by jmaustpc »

Its cooled down over the last few days, it got so cold outside here that with the wind causing winds chill, it was so could that I actually decided to put a light jacket on over my shirt. :) So we went from days in the 40s to a few days in the 20s. Since I last posted we have only had smoke on one day. The wind has still been around but otherwise its been a great improvement! :)
jmaustpc wrote: Tue Feb 04, 2020 7:17 am Has now exceeded 83 thousand hectares
The Canberra group of fires is now over 107 thousand hectares, two of these fires are still officially "out of control".
According to the ACT website about 4 hours ago (4:30pm)
Burnt perimeter size within the ACT remains at approximately 134 km, 60 km has been successfully extinguished, leaving 74 km of active fire edge
i measured the area burnt by this group of fires with some mapping software, its about 58km along its longer axis from about north west to south east and seems to average about 20km across in the other axis at 90 degrees to the 58km axis.


This is Australia, so of course what do you think a drought or massive series of bushfires would end with? .....Yeah, a FLOOD!!! :roll:


Australia being the size it is means that you will hear that we got rain but ....it will only be in some parts of Australia. Its a bit like if you live in Norway would you expect any rain in southern Italy to have any effect on you or your weather?

The east coast of NSW has had massive rainfalls and more is predicted over the next few days. The highest recorded rain fall in the last 24hours was in the north of NSW at Byron Bay where they got 283mm within 24 hours! Sounds good, but its been so extreme that some rivers are now predicted to possibly flood. Including a possibility of the Hawkesbury/Nepean river flooding, in western and north of Sydney. The rain was heavier up north from across the border in QLD and reduced as you go south down the coast until there was none down in the far south coast. That 283 mm in 24 hours up north is more than I have had here for about the last two years due to the drought, and we got nothing here.

There has been no rain recorded in the area where the Canberra fires are burning. The rain almost completely only fell on the coastal side of the Great Dividing Range (which runs more or less the whole way down the east coast of Australia) so a lot of the country will get little or no rain. So far there has been no rain on the far south coast where some bushfires are also still burning, but it might rain there over the next few days. Rain inland from the Great Dividing Range is only predicted to be sporadic over the next few days.

Another problem with this heavy rain is that a lot of the burnt areas are bare earth with a layer of ash that will wash into rivers and in some cases put so much ash in the rivers that it might kill the fish in the rivers.
chrisb wrote: Tue Feb 04, 2020 8:08 am In the video I can see heavy wind going through the trees. Is that an implication of the fire drawing so much air or rather its cause for spreading?
Hi Chris, actually both or either depending on which fire/day etc. In some places and times these fires have been large enough to create their own weather/wind, its common that when a powerful fire approaches there can be localised wind changes. You will hear people say something like the "fire came from several directions at once". The heat is so extreme in some cases that the fire sucks air into it. The smoke from some of those extreme fires down south was getting up over 40thousand feet, that's about the maximum height at which a modern passenger jet can fly. I noticed in one of those interviews that the man says the wind was blowing the fire towards them, then suddenly the wind changed direction then a second later the trees/bush just exploded in flames taller than the trees! That sounds like the fire was sucking in air in front of the flame front powerfully enough that it sucked harder than the wind speed once it was extremely close.

One day here a couple of weeks ago the wind was very strange, it normally blows from one or two directions for some time but on that day a strong wind kept changing direction all over the place every few seconds, it was really strange.

By the way, spotting (new fire started from falling embers) is very dangerous as a fire approaches and it can catch you by surprise. One of these recent fires was reported as having spotted 12km ahead, but you also see this at much shorter distances and the shorter the distance usually the more fires spot. The heat from even a small flame about waist high is extraordinary as you get close, and those large fires will roast you at quite a distance just from the radiant heat. That is why you see all the fire fighters covered up even on 45deg days. Imagine you are standing there with your hose as the flame front approaches, then as the heat very quickly gets more than you can tolerate you start to run backwards while spraying out water to try to reduce the heat and slow the fire, then sudden you realise that there is another fire behind you started by the spotting. Very dangerous......

Fighting a bushfire (as the fire front approaches you its somewhere between thrilling, exciting and utterly terrifying), if you have the right gear, experience/knowledge, in the right circumstances you can survive and make a big difference but if you miss judge anything or something breaks or goes wrong you can very quickly be dead! Perhaps a bit like sky diving when you think about it. :)

Anyway the scale of these fires and their ferocity have abated, what happens now depends on the weather. But it seems obvious that the worst and it may be all over soon. So I will drop this from an announcement to a normal topic.

The clean up is going to be a massive undertaking. Just two council areas on the south coast said that they have a estimated combined rubbish disposal requirement on 800 thousand tonnes from burnt buildings, etc.. Buildings are also a big problem if they are older than the late 1980s since they will likely contain asbestos based products, hence require dumping asbestos approved dumps. They said about a week ago that their rubbish dumps were damages by the fires and some were still on fire, but regardless the expected volume of waste is so huge that they will have to create some new dumps. All of that is only two council areas, maybe half of the south coast fire area, and does not include all the rubbish from all the other fires in the state or country. Just think how many trucks movements will be needed to dispose of even just that 800 thousand tonnes from that one small area!

Jim
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Re: Bushfires in Australia

Post by jmaustpc »

Exciting news, they announced on the news tonight that all of the 24 fires that are still burning in NSW have finally been contained!

Some of you might be surprised that so many are still burning.

We got an enormous amount of rain down the coast (more in the north), but comparatively little fell west of the Great Dividing Range, even less in the south. Along the coast in many places they got months worth of rain over 4 days. A huge dump landed in and around Sydney causing considerable flooding. On Monday people were asked to stay at home if possible, various roads and train lines were flooded etc. about 40 schools were closed but not out where we live, much to my children's disappointment. :)

If you don't know the area then this video might not mean much but it shows the flooding of the Hawkesbury River on the western edge of Sydney around Mulgrave, Windsor, Richmond and Pitt Town, from a drone. They are building a new bridge across the Hawkesbury river at Windsor, you can see it but immediately next to it upstream, the current older bridge is under water. At the very beginning of the video you get a view of the curved high level road bridge from Windsor across the flood plain to Mulgrave, the bridge was built a bit over ten years ago to allow for emergency evacuation of Windsor if a very large flood occurs. The other roads in/out of Windsor are several metres under water. This flood is only the smaller end of the range of heights (about half the height) that floods have historically reach in that area. The video goes for quite a long time, but if curious what on the link below... :)

https://www.youtube.com/watch?v=EpPf4d-oikg

About 3 weeks ago I drove over the Blue Mountains via the "Bells Line Of Road" with my daughters, into Sydney. If any of you are curious, this road goes over the mountains from Lithgow in the west to North Richmond on the east, (the western edge of Sydney). Its a distance of about 75km or so. This road goes through the area burnt by the Gospers Mountain mega fire (this fire alone burnt in excess of 500thousand hectares, yeah it was over half a million hectares in just that one fire). My daughters' reactions were interesting. As we got to the edge of Lithgow they suddenly saw the completely burnt to the top trees around the houses on the edge of town, they just stared out the windows, gasped and then went completely silent. Pretty much the entire first half from Lithgow to Mount Tomah botanic gardens looked..... well how do I describe it? One of my daughters at one point just said "Dad it looks like its been hit with an atomic bomb, the poor animals, they couldn't have survived that and even if they did what would they eat there has been nothing for kilometres". The fire fighters managed to save about half of Mount Tomah Botanic Gardens and about 90% of the building from there to where the fire was finally stopped at Kurrajong Heights, so although burnt it mostly looks less extreme. My girls were rather upset when they saw the burnt out pile or rubble and twisted metal that was all that was left of one of their favourite cafes. We used to stop there for a snack sometimes for a break, when driving through there and it had been a lovely little place. It was an historic little cottage with tables in a nice little garden that my girls seemed to like. My girls liked the people who ran it and their food.

Anyway, one of my daughters took some photos as we were driving, they were only on my mobile and are not all that good. But if some of you are interested in seeing them, let me know and then I will attach some here.

Jim
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Re: Bushfires in Australia

Post by chrisb »

Good to hear it is over - for now. And I would like to see some of your daughter's photos.
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Re: Bushfires in Australia

Post by triplus »

Good to hear the situation is under control, will likely take years for things to become normal again.
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Kunda1
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Re: Bushfires in Australia

Post by Kunda1 »

Thanks for the very picturesque updates. Glad to hear there is some regulation of the fires happening. Please do attach photos!
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Re: Bushfires in Australia

Post by jmaustpc »

Only 20 fires left now.

We have seen fire like this in some areas before but not all over the place, not at the same time, not for so long and not starting so early. The firefighters I have spoken to also said that at times the intensity and the fire behaviour were unusually extreme. Also the time and area which burnt with a high intensity was unusual.

Anyway some photos! :) These are taken by my daughter who had difficulties getting reasonable photos as in most we were driving at the time and she only had my mobile phone, hence the quality is not the best.

If you want to know where these were taken, they are from Lithgow up the "Bells Line Of Road" to about Mount Tomah.

Coming up the hill out of Lithgow, into the Blue Mountains....Note the one green tree, it should buy a lottery ticket! Literally one in how many million, the fire must have been pushed away by a sudden change in wind as it swirled around the mountains....
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jmaustpc
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Re: Bushfires in Australia

Post by jmaustpc »

looking out over Lithgow as the road winds its way up the hill....
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Continuing winding up the hill above Lithgow....Note that a small number of trees still have some green leaves at the top but most are brown/burnt...this shows you just how ferocious the fire was and how high the flames where as those few green leaves where the only bits not in flame. In other words, the flames where as high or higher than most of even the tallest of those trees in these photos.
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Note the grey ash all over the ground ....
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jmaustpc
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Re: Bushfires in Australia

Post by jmaustpc »

These 4 were taken just off the road, at the top of the mountains above Lithgow, there is a track leading into some old ruins of some anti-aircraft gun emplacements and bunkers. These would have been to protect the now disused airstrip on the other side of the road and Lithgow during the second world war. This is not far from where the old zig-zag railway meets up with the road on its way from Lithgow to Clarence. Its the original historic railway route between Lithgow and Clarence.

If you are interested in history, then after a fire like this is a great time to explore things like this, and old road alignments etc.
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jmaustpc
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Re: Bushfires in Australia

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The bush here had been so thick that it was difficult to push your way through, my eldest daughter and I went for an explore through some of it near here about a year ago, it was hard going,
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My daughter took these to show you how you could see the burnt bush going on "forever"....you can see out over the seemingly endless bush for several tens of kilometres in several places along the road ...and its just all burnt...
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