Author Topic: 20th January 2005 - Storm outbreak  (Read 9666 times)

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Offline Michael Thomas

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20th January 2005 - Storm outbreak
« on: 05 July 2011, 11:34:02 AM »
The day of the Coonabarabran tornado. See below for info on the tornado and model analysis/satellite images-

http://www.australiasevereweather.com/storm_news/2005/docs/200501-04.htm

Early development west of Marulan. Nice structure with good updraft/downdraft seperation. I suspect this later developed into the storm that moved through the Berry region. I left this storm for stronger storms further south-


Hail at Lake Bathurst, I arrived just after the main storm and was hit by small (0.5 - 1 cm) hail from a seperated storm-


Tree damage west of Berry on the road that heads to Kangaroo Valley. These photos were taken several days after the event-





Sydney radar loop (note, I did not make this gif file, I downloaded it from another website many years ago)-


Damage west of Berry seems to coincide with a strong storm merging with another storm to its north. This then forms into what appears to be a HP supercell which moves out to sea south of Kiama. Another supercell develops to the NW of this storm which then moves directly over Kiama. The radar presentation of the later supercell is very nice. I would have to think that the damage west of Berry was caused by straight-line winds. The damage path width is relatively wide and the damage is not very severe (for a tornado anyway). Also, most of the damage seems to indicate strong westerly or south-westerly winds. Though, I suppose a tornado can't be ruled out.

Michael



« Last Edit: 05 July 2011, 01:16:52 PM by Michael Thomas »

Offline Jimmy Deguara

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Re: 20th January 2005 - Storm outbreak
« Reply #1 on: 05 July 2011, 02:21:14 PM »
Hi Michael,

I cannot tell either way. The storm on radar seems to deviate into an easterly direction and slowly intensifies. Based on the conditions of the day with strong inflow winds, I cannot rule out tornadic winds causing the damage. The sheared off nature of the trees indicates sudden wind blasting the area. Was it from inflow jets and RFD winds or downbursts or both. Inclonclusive either way.

However, picking out some of the tornado damage in Australia is not always a clear-cut decision.

Thanks for posting!

Regards,

Jimmy Deguara
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Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #2 on: 06 July 2011, 06:48:07 AM »
Hi Jimmy,

Thanks for your comments. Unfortunately I have never inspected damage from a confirmed tornado therefore it is difficult for me know what to expect. The things that may hint towards a tornado is that several large trees or branches appear to have been brought down in different directions (maybe up to 90 degrees difference). Also, the nature of the damage is very random. As can be seen in the first image, one section of forest was totally destroyed (every tree snapped) then nearby trees showed little to no damage. This may be simply due to the topography. Honestly though, I know so little about what to expect that I can't make any definitive statements.

The radar image below I find interesting-


The southern storm is well and truely in the process of merging with the northern storm. If you look closely though, there may well be a hook on the southern cell. Seems to really be embedded in rain if that's the case. Unfortunately the resolution of the radar is quite poor and radar images were only recorded every 10 minutes. When it comes to tornadic events, 10 minutes is a long time! I am still leaning more towards this being non-tornadic damage, still worth considering though.

Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #3 on: 07 July 2011, 07:53:14 AM »
Does anyone know when the images for google maps were taken? I have found what appears to be damage from the Berry storm in Google maps. Very localised but seems to fit with the photos taken above. However, I also looked for Coonabarabran tornado track and could not see damage (edit: actually having another look, I might of missed it before. Still not as clear as I was expecting). Obviously the Coonabarabran tornado was quite destructive so should be visible.
« Last Edit: 07 July 2011, 08:28:14 AM by Michael Thomas »

Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #4 on: 07 July 2011, 12:15:14 PM »
I looked up the location of the damage west of Berry on google maps and it does appear that damage can be seen on the satellite image. It would appear that this damage fits very well with the photos above. I am assuming these satellite images were taken some time after the 20th of January 2005, how long I do not know (if they were taken before then I am just making a fool of myself :)). I have attached an annotated google maps image below-



Here is the direct link to google maps page to zoom in on the relevent areas-
Kangaroo Valley Rd to Kangaroo Valley Rd - Google Maps

This seems to indicate a damage path of up to ~1.5 km long and possibly up to ~200 m wide. This may add further support that this was actually a tornado. If this is the case, it would most certainly be on the lower end of the scale.

Michael

« Last Edit: 07 July 2011, 12:25:44 PM by Michael Thomas »

Offline Paul D

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Re: 20th January 2005 - Storm outbreak
« Reply #5 on: 08 July 2011, 05:39:29 AM »
Google Earth has the same imagery, (Digital Globe Coverage) and the date listed for the area you've highlighted is 30th Jan 2006.
The image where you've circled tree damage, also shows another small bit of image dating 16 Aug 2006 on the far left.

Cheers PD

Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #6 on: 08 July 2011, 06:40:15 AM »
Great news! Thanks Paul. So these images were taken approx. 1 year afterwards. Personally, I feel this supports that this was a tornado. Most of the damage I observed indicated strong westerly to southwesterly winds. This may be explained since I was observing damage on the northern edge of the damage path. A cyclonicly rotating tornado would have westerly winds on its northern side. The section I did see on the southern edge of the damage path on Kangaroo Rd was disturbed by work that was done to re-open the road.

Two things would be needed for 100% confidence. 1) I would need to confirm that I have correctly assigned the location where the photos were taken and 2) survey the damaged sections of forest. I would expect that on the southern edge of the damage path that trees/large branches would indicate easterly winds if it were a tornado.

I am very interested in other peoples opinions. How strong is the evidence in your opinion? Feel free to question any thing I have said.

Michael


Offline Paul D

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Re: 20th January 2005 - Storm outbreak
« Reply #7 on: 09 July 2011, 08:16:23 AM »
By swapping bettween different imagery dates in Google Earth you can get a fairly good idea of the tree damage/which ones are missing etc
(Imagery coverage/dates for this location are surprisingly good 13 July 2004, 30 Jan 2006, 16 Aug 2006)

here's what I could pick out


The damage appears to start at the west side of a flat app 2.3 km WSW of where the damage track crosses the Kangaroo Valley Rd.
I've circled in red the areas that appear to sustained the greater damage.
The dashed red lines indicate the app limit of visible tree damage (on the imagery), where earlier (2004) imagery is available
The dashed orange lines are apparent visible limit of tree damage where there is no earlier imagery to check against.

In the area on the east side of Irvines Rd there appears to be a number of trees that have fallen in different directions E SE Nth NW etc
But without being able to see on the ground this could always be a result of the trees being cut down rather than blown over.

Where the path crosses the ridge at the southern end of a plateau app 1.5km WSW of Kangaroo Valley Rd the visible damage appears patchy and  identifiable damage appears more limited to a few larger trees on the Western and Eastern slopes of the ridge.

The only tree damage outside the dashed path appears to be a couple of downed trees app 300-370m NNW of the large White shed at the property 600m west of Kangaroo Valley Rd damage path crossing. This is at the base of the ridge slope on the Nth side at the eastern end of the plateau. This tree damage could possibly be as a result of wind interaction/amplification due to terrain?

I'll leave more detailed interpretation of the whether it is tornadic damage or not to others.
But to me a path of extensive damage around 3.7km long and up to 300m wide, that appears to have varying degrees of damage along its length and appears not consistant to me seems at first glance to more suggestive of tornadic damage.
Having said that appart from the trees at the eastern end near Irvine Rd which may or may not represent all wind damage. The rest of the visible felled trees, where the direction they have fallen is visible, are all laying to the East or SE, possibly more indicative of straight line winds.
Also interesting is that the damage path appears to cross 4 areas with a number of buildings. Although some of the immediate grounds seem affected only one structure (at the western end of the damage path) appears not to be in the same state after the event in 2006, although it is one year on.

Good spotting for picking this damage detail up on the imagery Michael, as it is't often the imagery dates (in Oz) fit well with the damage event dates (and Google hasn't been consistantly updating much in the way of highres imagery for a while)

Paul
« Last Edit: 09 July 2011, 09:49:44 AM by Paul D »

Offline Jimmy Deguara

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Re: 20th January 2005 - Storm outbreak
« Reply #8 on: 10 July 2011, 07:46:10 AM »
Hi Paul,

That is an excellent survey and great use of available internet resources!

Keep the discussion ongoing and I hope others can also make a comment or two about their thoughts. Based on that last path map, and the conditions on the day, I would lean towards tornado!

Regards,

Jimmy Deguara
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Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #9 on: 11 July 2011, 06:58:34 AM »
Agree with Jimmy on both counts. Excellent work there Paul. Do you have access to higher resolution than available on the standard google maps?

I favouring that it was tornado as well. It seems the most reasonable explaination. I should add that photo no. 4 in my first post was taken facing west. This location was also on the southern edge of the damage path. One tree has lost bark on its eastward facing side. Presumably this occurred from a tree falling onto it. Also, I think how the tree trunks snapped may give some indication of wind direction. This may be an important bit of information to some one with greater knowledge on wind/tornado damage.

Lastly, I did hear that a waterspout was seen off Kiama that day as well. Not sure how accurate/this report was since I did not hear this directly off someone how saw it. May well be a case of chinese whispers. However, given the nature of the storm in question it may well be accurate.

Edit:

Here is the photo mentioned before. This was taken on the southern edge of the damage path facing roughly west-


I have maked out several features which suggest damage NOT caused by a strong west or south-westerly winds. This, together with the damage path, radar images and atmospheric conditions on the day, strongly supports that this was tornado damage. I think all the pieces of the puzzle are in place leaving little doubt in my mind. Very interested in other peoples opinions. Free free to disagree with my assessment.

Michael
« Last Edit: 11 July 2011, 04:49:32 PM by Michael Thomas »

Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #10 on: 12 July 2011, 01:43:05 PM »
In this article, the damage is reported to be the result of a tornado-

http://www.lazyfish.com.au/KVVoice/feb05.pdf

Offline Jeff Brislane

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Re: 20th January 2005 - Storm outbreak
« Reply #11 on: 13 July 2011, 08:12:29 AM »
Hi Everyone,

I witnessed this damage myself as well shortly after the event back in 2005. At the time i posted a breif report with photographs of the damage on one of the forums, (I can't remember which one). I also emailed some stuff to the BoM's Sydney office but they never replied. I always believed this damage was tornadic due to the nature of the damage being intermittant and in a relatively straight and narrow line over a few hundered meters (which could be caused by a tornadic vorticy from the parent thunderstorm "hopping" along the ground). The radar also showed features indicative of a supercell plus the meso-scale system also spawned at least one other tonadic supercell and lastly the alititude of the damage is also quite high (around 500m asl I think) which also lends weight to a torndao as it brings the surface closer to the cloud base circulation. It's also likely that as the storm came over the ranges at this point it could have been influenced by a stronger north easterly which could have aided breif tornado development. Anyway it's nice to see this event again and I'll dig around for my photos.

Regards Jeff.

Offline Michael Thomas

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Re: 20th January 2005 - Storm outbreak
« Reply #12 on: 14 July 2011, 11:39:17 AM »
As far as I am aware, there is no report of a tornado at this location on the BoM database. Given that the evidence is looking fairly convincing, I was thinking of contacting the BoM. Any advise with this? I guess one interesting point to make is that there appears to be no sightings of a funnel/tornado. You would think that a tornado with a ~3.7 km track would be seen in that area. One possible explanation may be that the tornado was wrapped/hidden by rain. This seems to make sense since there was a storm to the N/NW which was putting rain into the updraft region.

Finally, Paul, if you read this - "In the area on the east side of Irvines Rd there appears to be a number of trees that have fallen in different directions E SE Nth NW etc." Where are the trees that have fallen to the N or NW in relation to the damage path (ie north or south)?

Michael

Offline Paul D

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Re: 20th January 2005 - Storm outbreak
« Reply #13 on: 15 July 2011, 07:00:36 AM »
access to higher resolution than available on the standard google maps?

I haven't found any better resolution online imagery for this area.

However NSW Lands Dep do have air photo coverage around the right date:- 16th April 2006 for the area and at 1:25000 hard copy airphotos or even better enlargements of the specific damage area should give better resolution (esp viewed in 3D) than Google and may give a clearer idea on damage details.

http://www.lands.nsw.gov.au/airview/

Map name- KIAMA, Map No.- 9028
Photography Date- 16 Aprill 2006
Film No- 4959, Scale- 1:25000
Run- 1 Photo- 7 centers on damage area Photos- 5,6,7,8,9 full (3D) coverage

As for the trees which again "may" be damage related to the event they lie bettween the orange dashed lines on the earlier image
and are roughly centered in the of the damage path, there may be further evidence of damage just to the east of this as the terrain drops away but without earlier imagery to check against I didn't highlight this as it is not well defined.

Here's what it looks like to me, note they are all "possibles" in relation to direction and cause.(brighter colour arrows appear to be a little more defined?) Better imagery ie air photo enlargements may shed more light on this so long as they weren't cleaned up in the interim.


Cheers
Paul

PS:- WA has a pretty good selection of imagery online

https://www.landgate.wa.gov.au/bmvf/app/mapviewer/
example:- Australind
Mar 2006

Nov 2007

Nov 2010



« Last Edit: 15 July 2011, 07:08:29 AM by Paul D »

Offline Jimmy Deguara

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Re: 20th January 2005 - Storm outbreak
« Reply #14 on: 15 July 2011, 02:00:04 PM »
Hi Thomas,

Going to or contacting the Bureau may be helpful but first, I would go chat with people who own farms along the path. They may have images or even video or recollections. Just get some idea from them that you are doing a case study on the storm. I would get them to describe what they saw first and without hints and then perhaps after several questions ask them if they saw any funnels, noise, etc. Ask them did they take any picturesor video of the storm, or if any interesting features and obviously of the aftermath.

I have done this in the past for other tornadoes with mixed results.

Regards,

Jimmy Deguara
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