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#1418731 - 28/03/2017 21:40 Experiences with cyclones
Hanrahan Offline
Cloud Gazer

Registered: 11/03/2017
Posts: 27
Loc: Townsville
Guys, I'm not wanting to start a pissing contest here but I have lived most of my three score and ten in Townsville, enduring two direct cyclone hits and Yasi.

The most severe of these, in my little corner of the world, was Althea. It scared me and I have never taken cyclones lightly since. I was living in Garbutt where there is no high ground between me and the sea so we copped the peak winds, unattenuated. By the grace of some God [I'm atheist], the commission home we were in survived unscathed but many, built by the same builders were destroyed, I watched the roofs roll up like sardine tin lids.

This is where some will disagree, but no major community copped "unattenuated" Cat 3/4 winds today excepting the Whitsunday Islands and, I suppose some coastal communities south of Schute.

Cyclonic winds can be likened to knives, blunt [like the ones you set the table with], still blunt [like that of a non-cook who can't use a steel, sharp [like my kitchen knives, I can use a steel] and razor sharp [these can inflict serious damage]. Drag the edge of a razor sharp knife across the edge of your bench and it quickly becomes merely sharp.

Now it is only winds coming directly off the sea that are razor sharp, and they can inflict severe damage. While Althea destroyed many houses in Garbutt, a house I owned in Aithenvale only suffered minor damage, the edge had been taken off the winds in those few kilometres and deflecting around a couple of hills.

Today Bowen was always north of the eye so the winds travelled quite a distance over land, Shute Harbour township similar, and it was protected by high ground.

My point is that while residents have suffered sleepless nights [me too at times] and many will suffer damage and be without power for days, and I feel for them, Debbie could have been much worse. But still, it never was likely to match the hype.

Why the hype? There are millions in Federal aid dependant on the category, damage, deaths and hype. And [I might be stirring a hornet's nest here] BOM has a dog in the AGW fight. "Cyclones may be becoming rarer, but they are more intense" sort of thing.

Tracey and Althea were over 40 years ago now and both were intense, Tracey was our worst natural disaster, IMO because I don't trust the official death toll.

Personal thoughts and observations only.
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We'll all be rooned, said Hanrahan

Before the year is out.

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#1418885 - 29/03/2017 11:27 Re: Experiences with cyclones [Re: Hanrahan]
S.Novaehollandia Offline
Weather Freak

Registered: 18/03/2015
Posts: 63
That knife anaolgy is a poor bow to draw as wind shear is hundreds if not thousands of
feet in altitude. Take TC Winfred as one recent example. Following (largely) the GDR she stripped all vegetation from Gordonvale to the back of the Towers.. much of it at 2500feet or better.
Also as land surface topography creates it's own 'mini' lows there can be significant
difference in building damage even 10klms onshore. Much of JCU's testing projects focus on this phenonomem (sp?).
Still good to read you are thinking of how effects might happen smile
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#1418887 - 29/03/2017 11:33 Re: Experiences with cyclones [Re: Hanrahan]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4277
Loc: Brisbane
Differences in building standards combined with topological factors.

The other important thing to note is that the rapid intensification that occurred when Debbie was getting fairly close to landfall likely limited the size of the storm surge. If Debbie had hit strong Cat 4 status much earlier and 500km out to sea I'm sure the surge would have been much higher.

We have gotten very lucky with storm surge on most of the major cyclone impacts in Queensland. One day that luck will run out and a major storm surge will hit a major population centre on high tide.

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#1418930 - 29/03/2017 13:50 Re: Experiences with cyclones [Re: Hanrahan]
KBO Offline
Weather Freak

Registered: 09/01/2015
Posts: 98
Loc: Cairns
Just my observation looking at different systems available.
eg. BOM radar and even down to the models like EC and GFS, they showed an elongation in the eyewall as Debbie started to interact with land.
I think it's possible that her eyewall had a more of a running track or kidney type shape from this interaction, I think it would tighten the wind at the ends and maybe accelerating it? then down the straights slowing it down or maybe vise versa.
This shape could also be a reason for completely different observations only a few kms away from each other also coupled with the lay of the land hills valleys etc ect.

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#1418965 - 29/03/2017 15:25 Re: Experiences with cyclones [Re: Locke]
S.Novaehollandia Offline
Weather Freak

Registered: 18/03/2015
Posts: 63
Originally Posted By: Locke
Differences in building standards combined with topological factors.

The other important thing to note is that the rapid intensification that occurred when Debbie was getting fairly close to landfall likely limited the size of the storm surge. If Debbie had hit strong Cat 4 status much earlier and 500km out to sea I'm sure the surge would have been much higher.

We have gotten very lucky with storm surge on most of the major cyclone impacts in Queensland. One day that luck will run out and a major storm surge will hit a major population centre on high tide.


The importance you point to was generated by BOM, what data was available at that
time did not reflect the call as accurate. As my claim and the like comments by others
at the time are simply deductions based on data gathering they hold no weight
when 'arguing' against the BOM call - part of the problem Hanrahan points to.
My take rests on the dithering TC Debbie exhibited as she moved SSW, escalated as the GBR became an 'obstacle' - she was struggling to find the warmer water. That late move due West, coupled with a further slow down, says she was in trouble doing the job under the influence of that ridge AND the GBR - why the GBR is a huge factor in intensity building and so those predicted tide surges touted. Cyclones much further North where the GBR is close to landfall
see limited surge if any, even on much lower core pressures than TC Debbie, and often a shrinking of intesity. I would not discount surge altogether but am of the belief surges of > 1.5metres is fanciful scaremongering, or mathematical largesse.
That said... all indications are these events are going to increase in frequency albeit possibly mostly of the scale of this event and like lesser storms.
So best we get to planning in doing something about that in the way of record and information__ in real time__.
I have posted my 'rant' on that way forward into Page 158 of the topic dedicated to TC Debbie.
Cheers.
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Storm Bird [ http://clubtroppo.com.au/2011/02/07/unpacking-the-yasi-hype/ ]

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#1418968 - 29/03/2017 15:31 Re: Experiences with cyclones [Re: KBO]
S.Novaehollandia Offline
Weather Freak

Registered: 18/03/2015
Posts: 63
Originally Posted By: KBO
Just my observation looking at different systems available.
eg. BOM radar and even down to the models like EC and GFS, they showed an elongation in the eyewall as Debbie started to interact with land.
I think it's possible that her eyewall had a more of a running track or kidney type shape from this interaction, I think it would tighten the wind at the ends and maybe accelerating it? then down the straights slowing it down or maybe vise versa.
This shape could also be a reason for completely different observations only a few kms away from each other also coupled with the lay of the land hills valleys etc ect.


Might well have been a cloning event happening, yes.
We do not have the instrument capability on the ground to know for sure.
At the time I saw it as the death throes of a spent force.
However only BOM has any 'say' in what history records.
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Storm Bird [ http://clubtroppo.com.au/2011/02/07/unpacking-the-yasi-hype/ ]

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#1422617 - 01/05/2017 23:18 Re: Experiences with cyclones [Re: Hanrahan]
Jennistar Offline
Cloud Gazer

Registered: 26/04/2017
Posts: 3
It was interesting for me to read about cyclones as you did it in a very interesting way.
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