Sunday, 2 October 2016

Google Maps recently updated there aerial imagery of Forbes Creek. The new images reveal the extent of the tornado damage path left by the 30 January 2016 event. The path revealed is 6,300 meters long with a maximum path width of at least 300 metres. The damage to trees done by winds of at least EF1 strength defines the limit of the path observable in the imagery. The bounds of this path allows for the easily location of pictures and video of structures damaged by the event.  The remote damage survey used the methodology set out previously (Shergold 2016A).

Synoptic Summary

Thunderstorms produced strong winds, heavy rain and local flash flooding in the Sydney region on the 29th and 30th, with damage to buildings and powerlines. Major property damage was also reported in the towns of Forbes Creek and Palmers Island (BoM 2016, p. 4). Conditions across the ACT and southern NSW were favourable for tornadoes with strong vertical wind shear and high amounts of low level moisture (Colley 2016).

Damage Survey


Event Summary

Start Date/Time: 30/01/2016 12:30:00 UTC
Start Latitude/Longitude:  -35.3907, 149.49111
Duration:  10 minutes
Maximum wind speed: 200-220 km/h
Enhanced Fujita Scale: 2
Path length: 6300 metres
Maximum Path width: 300 metres
Path direction:  0 degrees
End Date/Time: 30/01/2016 12:40:00 UTC
End Latitude/Longitude: -35.4464, 149.49093

Bibliography

BoM, 2016A Monthly Weather Review – Australia – January 2016, Bureau of Meteorology, viewed 3 October 2016, http://www.bom.gov.au/climate/mwr/aus/mwr-aus-201601.pdf
BoM, 2016B Severe Storm Archive – Tornado ID 1300, Bureau of Meteorology, viewed 3 October 2016, http://www.bom.gov.au/australia/stormarchive/
Colley, C 2016 ‘Tornado strikes south of Bungendore as Canberra cops supercell storm’, Sydney Morning Herald, 31 January, viewed 3 October 2016, http://www.smh.com.au/environment/weather/tornado-strikes-south-of-bungendore-as-canberra-cops-supercell-storm-20160131-gmi2o6.html
Francis, A, Fettes, J & Osborne, T 2016 ‘NSW storms: Forbes Creek couple watched 'bricks falling on the bed' during wild weather’, ABC News (Australian Broadcasting Corporation), 31 January,  viewed 3 October 2016, http://www.abc.net.au/news/2016-01-31/homes-destroyed-by-destructive-winds-during-nsw-storm/7127776
McDonald, J & Kishor, CM 2006 A recommendation for an Enhanced Fujita scale (EF-Scale), Lubbock, Texas, Wind Science and Engineering Research Center, Texas Tech University, 30 October.
Queanbeyan City RFB [QBNCAT1] 2016, ‘Forbes Creek Tornado impact map’, Tweet, 31 January, viewed 3 October 2016, https://twitter.com/QBNCAT1/status/693662629567471620
Queanbeyan City RFB [QBNCAT1] 2016, ‘Forest striped of foliage with full size gum trees cut clean in half #forbescreektornado’, Tweet, 31 January, viewed 3 October 2016, https://twitter.com/QBNCAT1/status/693674611070730240
Queanbeyan City RFB [QBNCAT1] 2016, ‘Debris field #forbescreektornado’, Tweet, 31 January, viewed 3 October 2016, https://twitter.com/QBNCAT1/status/693675126995300352
Shergold, D 2016A, 'Remote damage survey indicates tornado was culprit of Wyndham Vale damage on 18 March 2016', David's Blog, viewed 3 October 2016, http://davidsblog.bswr.com.au/2016/04/remote-damage-survey-indicates-tornado.html
Shergold, D 2016B, 'Tornadoes in two states 30/01/2016', David's Blog, viewed 3 October 2016, http://davidsblog.bswr.com.au/2016/01/tornadoes-in-two-states-30012016.html
Sills, DML, McCarthy, PJ & Kopp, GA 2014 Implementation and Application of the EF-Scale in Canada, American Meteorological Society.
Stormspotters AU, 2016 ** Forbes Creek Tornado** - 30/01/16, video, 30 January, viewed 3 October 2016, https://youtu.be/WErAY8f_VmQ
The Weather Chaser, 2016 BoM Canberra Radar Loop – Rain Rate – IDR404: 12:00 30/01/2016 UTC – 13:00 30/01/2016 UTC, viewed 3 October 2016, http://www.theweatherchaser.com/radar-loop/IDR404-canberra/2016-01-30-12/2016-01-30-13

Forbes Creek Tornado 30/01/2016

Wednesday, 17 August 2016

Tornadoes are a regular if uncommon occurrence in Australia. When events do occur in areas far from our nation’s metropolitan centres those with the expertise to record and analyse the damage left by these event are significant distances from the affected area. Additionally the resources available to meteorological organisations interested in studying these phenomena are limited.

The tornado that impacted areas east of Dubbo on 24 August 2015 is arguably the most well observed and recorded tornadic event in Australia’s history. Countless photos and multiple videos captured the event in progress and the damage left in its wake. Many of these images were published by news websites and individuals on social media platforms.

The event data available for the event in the Severe Storm Archive records maintained by the Bureau of Meteorology is incomplete and is as follows.

Tornado ID: 1282, Date/Time: 24/08/2015  6:00:00 UTC, Latitude: -32.2484, Longitude: 148.6012, Nearest town: DUBBO, District: Central Western Slopes and Plains, LGA: Blank, State: NSW, Postcode: Blank, Source: SES, Station number: Blank, Duration: 0, Min speed: 63, Max speed: 117, Fujita scale: 0, Path length: 0, Path width: 0, Path direction: 0, Damage total: Blank, Insurance payout: Blank, Number of deaths: Blank, Number of injuries: Blank, Comments: Jonny from SES called with report of a tornado at Dubbo around 5-5:15 PM. Police got some more calls with reports of partial roofs off houses and very strong winds. Jonny relayed this info through. Possible footage too. No GPATS over Dubbo at this time but there were a couple near Gilgandra. Tornado
This entry - as with many in the archive - is vague. The wind speeds in this tornado record are the generic minimum and  maximum wind speeds for a tornado rated F0 on the Fujita Scale. It is clear no damage survey was completed, as no path details have been entered. Therefore no rating was made based on surveyed damage.

Synoptic Summary

On the 24th, a complex low pressure system produced widespread thunderstorm activity as it crossed New South Wales, before intensifying into an East Coast Low as it tracked off the New South Wales coast on the 25th (MWR - Australia - Aug 2015, p. 5). Thunderstorm activity was widespread across northern and eastern New South Wales, and parts of the Darling Downs and Granite Belt in Queensland on the afternoon of the 24th, with 2-3 cm hail reported in many areas, including Sydney, the Blue Mountains, the Hunter Valley, and Boggabilla near Goondiwindi, as well as flash flooding that occurred in the Sydney CBD, with 22.2 mm of rain in 11 minutes at Observatory Hill on the evening of the 24th (MWR - Australia - Aug 2015, p. 3).



The Skew-T sounding available from Moree at 10:00 AM (23/08/2015 23:00 UTC) reveals an increased amount of shear (turning) in the lowest portion of the atmosphere.

Temperature, dew point, rainfall (weatherzone.com.au)
10m winds, gusts, pressure (weatherzone.com.au)

The 24 hour graph of observations for the 24th (EST) at Dubbo Airport show that the tornadic event was accompanied by a drop in pressure. The updraft that produced the tornado passed a few kilometers to the north of the airport about 10-20 minutes before the tornado touched down. These observations also confirm what is shown in all photographs and video that the tornado occurred a significant distance from any precipitation associated with the storm producing it, a low-precipitation (LP) supercell.

Remote Damage Survey

While no on-the-ground survey was carried out, sufficient evidence was published online to carry out a remote survey for the event. As previously demonstrated, remote damage surveying techniques using open source data mining of social media for post-disaster damage assessment are well recognized (Shergold, 2016 para. 4). The data available for this event offers another unique opportunity to explore the potential of remote damage surveys that can supplement on-the-ground resources available.




The conclusion that can be drawn from the remote damage survey is that this tornado was of at EF1 strength, producing damage consistent with winds 135-175 km/h over much of its 7 kilometre damage path. The maximum path width was at least 100 metres near the end of the documented path, at the same location where the most significant damage was recorded. This damage to a well constructed outbuilding (SBO) and  numerous mature trees suggest the tornado produced an area of EF2 damage in which the EF scale damage indicators provide good contextual confirmation for a mid-range EF2 rating. The footage captured as the tornado reached the mature climax of its destructive power demonstrates that the tornado was strong (Ross Sawtell, 2015).




Event Summary

Start Date/Time: 24/08/2015  6:00:00 UTC
Start Latitude/Longitude: -32.23358, 148.66879
Duration: 15 minutes
Maximum wind speed: 190-200 km/h
Enhanced Fujita Scale: 2
Path length: >7000 metres (7 kilometers possibly up to 10 kilometers).
Maximum Path width: >100 metres
Path direction: 310 degrees
End Date/Time: 24/08/2015  6:15:00 UTC
End Latitude/Longitude: -32.27793/148.71993


Bibliography


7NEWS 2015, Dubbo twister terrifies locals, 25 August, viewed 18 August 2016, https://youtu.be/tcd0J7hNuec
93.5 StarFM Dubbo 2015, on 93.5 StarFM Dubbo Facebook, 24 August, 8:08 pm, viewed 18 August 2016, https://www.facebook.com/935starfm/posts/1028307733876774
93.5 StarFM Dubbo 2015, on 93.5 StarFM Dubbo Facebook, 24 August, 8:59 pm, viewed 18 August 2016, https://www.facebook.com/935starfm/posts/1028330893874458
ABC Western Plains 2015, on ABC Western Plains Facebook, 25 August, 11:20 am, viewed 18 August 2016, https://www.facebook.com/abcwesternplains/posts/986152661405417
ABCB 2012, ‘Volume Two Class 1 and 10 Buildings’, National Construction Code Series, viewed 10 April 2016, ISBN 1-921453-80-9, https://law.resource.org/pub/au/ibr/au.ncc.2.2012.html
August 2015, Monthly Weather Review (MWR) - Australia, viewed 18 August 2016, http://www.bom.gov.au/climate/mwr/aus/mwr-aus-201508.pdf
Boujengles 2015, Tornado Over Dubbo NSW, video, 24 August, viewed 18 August 2016, https://youtu.be/71BHtbR-tKc
Boujengles 2015, Tornado Over Dubbo #2, video, 24 August, viewed 18 August 2016, https://youtu.be/utZXWR3YbVM
Cassie’s Fresh Eggs 2015, on Cassie’s Fresh Eggs Facebook, 24 August, 10:55 pm, viewed 18 August 2016, https://www.facebook.com/permalink.php?story_fbid=504768639679060&id=261973110625282
Edward Foran 2015, NSW Dubbo mini tornado, video, 5 December, viewed 18 August 2016, https://youtu.be/Ni9eZbKki3Q
Goldstein, K 2009, ‘The Janka Hardness Test for Hardwoods’, The Iaido Journal, April 2009, viewed 10 April 2016, http://ejmas.com/tin/2009tin/tinart_goldstein_0904.html
Hoar, J 2015A, ‘Dubbo cleans up after tornado with 16 'significantly damaged' homes’, Daily Liberal, 4:30 a.m.  26 August, viewed 10 April 2016, http://www.dailyliberal.com.au/story/3305237/dubbo-tornado-dubbo-cleans-up-after-tornado-photos/
Hoar, J 2015B, ‘Frame buckled under weight of tornado’, Daily Liberal, 4:30 a.m. 26 August, viewed 10 April 2016, http://www.dailyliberal.com.au/story/3305459/dubbo-tornado-frame-buckled-under-weight-of-tornado-photos/
Hoar, J 2015C, ‘No doubt Dubbo was hit by tornado: BOM’, Daily Liberal, 4:30 a.m. 26 August, viewed 10 April 2016, http://www.dailyliberal.com.au/story/3305443/dubbo-tornado-no-doubt-dubbo-was-hit-by-tornado-bom/
Hoar, J 2015D, ‘Truck tipped over, houses damaged: Dubbo cleans up after tornado’, Central Western Daily, 5 a.m. 26 August, viewed 10 April 2016, http://www.centralwesterndaily.com.au/story/3306258/gallery-truck-tipped-over-houses-damaged-dubbo-cleans-up-after-tornado/
Kellie Matterson 2015, Dubbo Tornado Smashing Richmond Estate 24-08-15 Rowey, video, 28 August, viewed 18 August 2016, https://youtu.be/LYCpAyOBiF0
Luis Ward 2015, Video shows tornado sweeping through..., 24 August, viewed 18 August 2016, https://youtu.be/x-PcdyMSZ6Q
Prime7 News, Tornado hits Dubbo, video, 25 August, viewed 18 August 2016, https://au.prime7.yahoo.com/a1/news/a/-/local/29346758/tornado-hits-dubbo-video/
Rayner, M 2015A, ‘Dubbo tornado: tornado hits Dubbo, destroys houses’, Daily Liberal, 6:16 p.m. 24 August, viewed 10 April 2016, http://www.dailyliberal.com.au/story/3302558/dubbo-tornado-tornado-hits-dubbo-destroys-houses-photos-video/
Rayner, M 2015B, ‘Dubbo tornado: tree blasts through home as tornado wreacks [sic] havoc’, 6 a.m. 25 August, viewed 10 April 2016, http://www.dailyliberal.com.au/story/3302912/dubbo-tornado-tree-blasts-through-home-as-tornado-wreacks-havoc-photos-poll/
Ross Sawtell 2015, Dubbo tornado - BEST NEW FOOTAGE - ROSS SAWTELL - 24.8.2015, video, 25 August, viewed 18 August 2016, https://youtu.be/Jf9WHkQkxZo
Schmidlin, T, Hammer, B, King, P, Ono, L, Miller, LS & Thumann, G 2002A, ‘Unsafe at any (wind) speed? Testing the stability of motor vehicles in severe winds’, Bulletin of the American Meteorological Society, vol. 83, no. 12, pp.1821-1830, viewed 10 April 2016, http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-83-12-1821
Schmidlin, TW, Hammer, BO, King, PS & Miller, LS 2002B, ‘Wind speeds required to upset vehicles’, submitted for publication to American Meteorological Society, viewed 10 April 2016, https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwifscfauoPMAhXjhaYKHRsyB7AQFggbMAA&url=https%3A%2F%2Fams.confex.com%2Fams%2Fpdfpapers%2F50675.pdf&usg=AFQjCNEpEKmlqeTfbQ__WHxU2aanzHz1qw&sig2=VLeLv7tok3sigyoa47pnYA&bvm=bv.119028448,d.dGY
Severe Storms Archive 2015, Tornado ID 1282, 24 August, viewed 18 August 2016,  http://www.bom.gov.au/australia/stormarchive/
Settree, John 2015, John Settree Facebook, 25 August, 8:02 am, viewed 18 August 2016, https://www.facebook.com/john.settree.3/posts/10206380782091562
Shergold, D 2016, 'Remote damage survey indicates tornado was culprit of Wyndham Vale damage on 18 March 2016', David's Blog, viewed 18 August 2016, http://davidsblog.bswr.com.au/2016/04/remote-damage-survey-indicates-tornado.html
Skye 2015, Dubbo Tornado 24th august 2015, video, 26 August, viewed 18 August 2016, https://youtu.be/MbcStbMu8Fs
Storm Spotters Australia (Shelly Bourke) 2015, on Storm Spotters Australia Facebook, 24 August, 7:30 pm, viewed 18 August 2016, https://www.facebook.com/stormspottersaustralia/posts/738304119631698
Todd S 2015, Dubbo tornado from the start, video, 24 August, viewed 18 August 2016, https://youtu.be/Lbwzk3P_2zI
Troutman, B 2015, on Brandon Troutman Facebook, 24 August, 5:28 pm, viewed 18 August 2016, https://www.facebook.com/brandonleetroutman/videos/10154127761905299/
Weatherzone 2015, Dubbo Ap 24 hour history graph of temperature, wind and rainfall, 24 August, Viewed 18 August 2016, http://www.weatherzone.com.au/station.jsp?list=ob&lt=site&lc=65070&of=of_o&ot=ot_b&ut=1&dt=24%2F08%2F2015
What’s On In Dubbo 2015, on What’s On In Dubbo 2015 Facebook, 24 August, 7:48 pm, viewed 18 August 2016, https://www.facebook.com/WhatsOnInDubbo/posts/760026100786637
What’s On In Dubbo 2015, on What’s On In Dubbo 2015 Facebook, 25 August, 8:02 am, viewed 18 August 2016, https://www.facebook.com/WhatsOnInDubbo/posts/760267877429126
WIN News Central West 2015, on WIN News Central West Facebook, 26 August, 3:46 pm, viewed 18 August 2016, https://www.facebook.com/431557963627074/videos/819443571505176/

Social media links to content including images and videos are not perminent. This may result in some dead links and unavailable content.

Dubbo Tornado - 24 August 2015

Wednesday, 6 April 2016

After this event occurred it took only a few hours for the Bureau of Meteorology to dismiss the possibility that a tornado had occurred (Irving, 2016C). I started this remote damage survey expecting the event not to be a tornado, possibly a microburst, but most likely I expected this survey to be inconclusive. 


There was one potentially credible witness who said, "I've only heard that noise once before and it sounded like a mini-tornado" (ABC, 2016). Identifying a tornado by only its sound because you've heard one before maybe possible, but unlikely to suffice as good evidence.

Radar data available publicly in Australia presents a significant problem when it comes to analysis to identify features related to tornadoes. This is because it is all composite radar images, not the base reflectivity scans typically needed. The Doppler radar wind at the time has subtle, but identifiable indications of mesocyclonic activity associated with the northern end of a bowing line segment of storms visible on the rain rate radar.


The remote damage survey has used open source data mining of social media; searching websites including Google, Twitter and Facebook for photos and videos of the damage. The potential of crowd sourcing photographs (Baker & Foulser-Piggot, 2015; Kim, Pant & Yamashita, 2015) and social media data mining (Kryvasheyeu et al. 2015) as post-disaster damage assessment vehicles has been well recognized. After the Moore, Oklahoma tornado of 2013 passive and active data mining of social media was used to identify damage locations within the bounded storm areas using geo-located tweets in real-time (Graettinger et al. 2014, p. 29). The images mined from Twitter after the Moore tornado proved useful in establishing how much cleanup had taken place before personnel from the damage survey team had arrived to make their assessment.


Once images of damage were sourced, those that had associated location information in captions, articles or associated posts were utilized first. Locations were searched for on Google Maps, satellite/aerial imagery enabled specific identifiable features in pictures to be located from above. These locations were then checked via Google Street View for accuracy, just as done during the Moore 2013 damage survey (Graettinger et al. 2014, p. 27). Pictures that lacked location information were then located by visually searching the areas in proximity to the know location of damage.





Once complete 13 locations were identified as having sustained damage at Manor Lakes estate in Wyndham Vale. When mapped, the damage formed a line just over 500 meters long and little more than a house wide (mostly less than 25 metres, max width 40 metres). When a straight line is plotted from the location of damage furthest west to the location of damage furthest east, all the observed damage has occurred within 20 metres of that line (map markers placed in the centre of damaged structures).



Not only did the damage form a narrow defined path, it also presented wild variations in wind direction (completely reversing direction in less than 10 metres at one point). The final evidence that points clearly at a tornado are three examples of items being picked up and carried unknown distances away (I did not find reports they were found). These items included a trampoline and air-conditioning units from two separate houses. The removal of air-conditioning units where they have been carried away is indicative of a tornado, not straight line winds or a microburst.


Using the Enhanced Fujita (EF) Scale to estimate wind speeds, this tornado was an EF0 with winds 105-137 kph. Almost all (12 out of 13) of the damage indicators were one and two family residences (FR12 DI2), of these 6 had sustained the threshold of visible damage (DOD1 Expected 118 kph, Lower bound 98 kph, Upper bound 141 kph). The other 6 had sustained a degree of damage that included the loss of roof covering material (<20%) and/or gutters (DOD2 Expected 126 kph, Lower bound 101 kph, Upper bound 155 kph). The last damage indicator was an adolescent eucalyptus tree (hardwood) having all its large branches (25-76 mm [1-3 inches] in diameter) broken (TH DI27 DOD2 Expected 118 kph, Lower bound 98 kph, Upper bound 141 kph). If considered akin to the hardwood trees categorized in the EF Scale, this can be a usable damage indicator.

The new construction of all these buildings gives confidence in ascribing the expected wind speeds for the degree of damage done (this assumes they met building codes). The proximity of damaged structures to one another provides excellent contextual and numerical confirmation for this rating.

Although this study is not comprehensive, focusing heavily on the damage evidence, it does makes the case that further investigation of this event is warranted.

References

7 News Melbourne [7NewsMelbourne] 2016, ‘Melbourne lashed by wild weather. Wyndham Vale appears to be worst hit suburb. @laurelirving7 has an update.’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/7NewsMelbourne/status/710626956589412352
ABC 2016, ‘Wild weather causes building damage, fallen trees in 'mini-tornado'’, Australian Broadcasting Corporation, 18 March, viewed 7 April 2016, http://www.abc.net.au/news/2016-03-18/wild-weather-causes-building-damage-fallen-trees-in-victoria/7257050
Anderson, S [skateanderson] 2016A, ‘A housing estate at #wyndhamvale has been particularly hard hit by the #Melbourne storms @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710602375615000576
Anderson, S [skateanderson] 2016B, ‘Residents say it was like a tornado ripped through the streets @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710602508029145088
Anderson, S [skateanderson] 2016C, ‘An air conditioning unit was ripped off the roof here. The owners can't find it. @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710603949452042240
Anderson, S [skateanderson] 2016D, ‘Some pretty serious roof damage at Manor Lakes estate in #wyndhamvale @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710605177846300672
Anderson, S [skateanderson] 2016E, ‘Wow. Fences torn up at #wyndhamvale @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710605274160041985
Anderson, S [skateanderson] 2016F, ‘High risk of tripping over roof tiles on the streets here @abcnewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/skateanderson/status/710605375360278530
Baker, H and Foulser-Piggott, R 2015, Use of crowd-sourced photographs in post-disaster damage assessment, paper presented at SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World, 9-10 July, viewed 7 April 2016, http://seced.org.uk/images/newsletters/BAKER,%20FOULSER-PIGGOTT.pdf
Davies, B and Duncan, J 2016, Wild weather across Melbourne and regional Victoria causes havoc, 18 March, viewed 7 April 2016, http://www.heraldsun.com.au/news/victoria/wild-weather-across-melbourne-and-regional-victoria-causes-havoc/news-story/78f084947b1a02a12ba3a3ed41df6ccb
Graettinger, AJ, Ramseyer, CCE, Freyne, S, Prevatt, DO, Myers, L, Dao, T, Floyd, RW, Holliday, L, Agdas, D, Haan, FL, Richardson, J, Gupta, R, Emerson, RN and Alfano, C 2014, Tornado Damage Assessment in the aftermath of the May 20th 2013 Moore Oklahoma Tornado, viewed 7 April 2016, http://eprints.qut.edu.au/81311/1/MooreTornadoFinalReport.pdf
Irving, L [laurelirving7] 2016A, ‘Andrew has lost his trampoline and aircon after freak wind went through Wyndham Vale. #7NewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/laurelirving7/status/710594376477466628
Irving, L [laurelirving7] 2016B, ‘Residents say they've never seen anything like it. They call it a mini tornado. #wyndhamvale #7NewsMelb’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/laurelirving7/status/710598207575752704
Irving, L [laurelirving7] 2016C, ‘Weather bureau says there was no mini tornado, but there were wind gusts 80-90km hr when front went thru. Widespread damage.’, Tweet 18 March, viewed 7 April 2016, https://twitter.com/laurelirving7/status/710611781098405888
Karl Kim, Pradip Pant, Eric Yamashita 2015, Disasters, drones, and crowd-sourced damage assessment, paper presented at CUPUM, 7-10 July, viewed 7 April 2016, http://web.mit.edu/cron/project/CUPUM2015/proceedings/Content/pss/339_kim_h.pdf
Kryvasheyeu, Y, Chen, H, Obradovich, N, Moro, E, Van Hentenryck, P, Fowler, J and Cebrian, M 2015, Nowcasting Disaster Damage, viewed 7 April 2016, https://arxiv.org/ftp/arxiv/papers/1504/1504.06827.pdf
Saban, A 2016, ‘Mini tornado hits Wyndham Vale street’, Star Weekly, 18 March, viewed 7 April 2016, http://www.starweekly.com.au/news/mini-tornado-hits-wyndham-vale-street/

Remote damage survey indicates tornado was culprit of Wyndham Vale damage on 18 March 2016

Tuesday, 16 February 2016

The early hours of February 24th 2013 saw a series of tornadoes impact Sydney's metropolitan area and through the Illawarra. Potentially tornadic events were reported across a wide area. The suburbs hit have linear groupings, with damage occurring along narrow swathes. From reports and images published by online media outlets I have reviewed the archived Doppler radar from the event and have concluded; in addition to the Bureau of Meteorology's three  confirmed tornadoes there are another six probable tornadoes that occurred, three of which there is enough evidence to do so.

Doppler radar reveals a very high number of mesocyclones occurring concurrently in a line of storm cells moving southwest. At 12:13 am the Sydney (Terry Hills) Doppler radar image contained eight identifiable mesocyclonic signatures (Figure 1). Images have been sourced from the BoM Weather Radar Loops Archive.

Figure 1: IDR71I Sydney (Terrey Hills) 24/02/2013 00:13 EDT (23/02/2013 13:12 UTC).

Beyond the damage reported, the Doppler radar indicates that potentially many more tornadoes occurred, either to weak to cause significant damage, or damaging areas not populated. Because this event happened in the middle of the night almost no one witnessed the events, and no one was able to capture any pictures or film of the tornadoes.

See : 128km Radar Loop for Sydney (Terrey Hills), 13:00 23/02/2013 to 14:00 23/02/2013 UTC


In the hour after midnight four tornadoes occurred. The first crossed Neutral Bay impacting Kirribilli. A second came ashore at Dee Why. The third damaged Fox Studios at Moore Park. And a fourth came ashore at Malabar, continuing inland to Chifley.

Figure 2: IDR71I Sydney (Terrey Hills) 24/02/2013 00:19 EDT (23/02/2013 13:19 UTC).

The first two tornadoes impacted Kirribilli and Dee Why just after 12:20 am. Figure 2 indicates the location of the mesocyclones responsible for these tornadoes. In addition to the radar evidence the event at Kirribilli was witnessed. The degree of damage at Kirribilli and Dee Why indicates the tornadoes were of EF1 and EF0 strength respectively.

Figure 3: IDR71I Sydney (Terrey Hills) 24/02/2013 00:37 EDT (23/02/2013 13:37 UTC).

Figure 3 indicates a mesocyclone over Sydney's eastern suburbs; comparable in strength to the one that spawned the Hornsby EF1 tornado of November 2013. It is this updraft that was responsible for the damage at Moore Park around 12:40 am. The damage at Fox Studios is consistent with a tornado of at least EF0 strength as the area of roofing removed exceeded 20% of the building's covering. Also indicated in Figure 3 is a much stronger couplet east of Randwick. It is this second mesocyclone that is responsible for the tornado that came ashore at 12:45 am to damage Malabar and Chifley. The narrow trail (tens of meters across) shows evidence of convergent wind damage and is consistent with a tornado of EF0 strength.

See : 128km Radar Loop for Sydney (Kurnell), 14:00 23/02/2013 to 16:00 23/02/2013 UTC


The Kurnell radar loop is clearer (less location names obscuring the images) for the events in Sydney's southwest and south of Wollongong. The 01:30 am Doppler wind scan shows a strong mesocyclone just east of Camden consistent with being responsible for the damage caused at Narellan, Mount Annan and Camden. The degree of damage described generally indicates a tornado of EF0 strength. The radar image at 02:36 am reveals a mesocyclone moving over Albion Park Rail. This tornado was the second (and last) to be witnessed during this outbreak. The damage at Albion Park Rail is consistent with an EF0 strength tornado.

See : 128km Radar Loop for Wollongong, 14:00 23/02/2013 to 17:00 23/02/2013 UTC


The last three tornadoes of the event were confirmed by the Bureau of Meteorology. Occurring at Jamberoo (3:00 am), Kiama (3:15 am) and Seven Mile Beach (3:25 am) through to Nowra, rated as EF0, EF1 and EF2 respectively. The Severe Storms Archive details the tornadoes' paths and duration. The Jamberoo tornado left a damage path 8 km long and had a max width of 75 meters, lasting 30 minutes (Tornado ID 1226). The Kiama tornado created a trail of destruction 1.6 km long with a max width of 100 meters, lasting 20 minutes (Tornado ID 1227). And the EF2 tornado that barreled from halfway between Gerroa and Seven Mile Beach to Nowra had a path: 15.7 km long and width of 250 meters, lasting 30 minutes (Tornado ID 1228).

Figure 4: Damage at Kiama. Image Credit Illawara Mercury

There is sufficient evidence to confirm the tornadoes at Kirribilli, Malabar and Albion Park Rail. It is highly probable that the damage at Moore Park, Dee Why and, Narellan through Mount Annan and Camden was caused by another three tornadoes.  A total of 9 possibly tornadic events occurred.

Tornado Outbreak Sequence Summary


  • 12: 20 am Dee Why EF0 (strong radar couplet)
  • 12: 20 am Kirribilli EF0 (witnessed, strong radar couplet)
  • 12: 40 am Moore Park damage of EF0 (radar couplet)
  • 12: 45 am Malabar/Chifley  EF0 (convergent damage, strong radar couplet)
  • 01:30 am Narellan/Mount Annan/Camden EF0 (strong radar couplet)
  • 02:40 am Albion Park Rail EF0 (witnessed, radar couplet)
  • 03:00 am Jamberoo EF1 (BoM confirmed EF0)
  • 03:15 am Kiama EF2 (BoM confirmed EF1)
  • 03:25 am Seven Mile Beach/Nowra EF2 (BoM confirmed)

It is remarkable to note that nobody was killed or seriously injured in this event.

Update 21/04/2016

A recent study by John Terrence Allen & Edwina Rose Allen, The Tornado Climatology of Australia 1795-2014  2nd Workshop on Severe Convection and Climate, 2016, Columbia University, New York confirmed 8 tornadoes, rating them on the Fujita Scale.
  1. Moore Park (F0)
  2. Narellan/Mount Annan/Camden (F1)
  3. Malabar/Chifley (F1)
  4. Kirribilli (F0)
  5. Seven Mile Beach/Nowra (F1)
  6. Kiama (F2)
  7. Jamberoo (F1)
  8. Albion Park Rail (F1)
Numbers are in reference to outbreak event map produced by Allen & Allen.

NSW Tornado Outbreak 24/02/2013

Saturday, 6 February 2016

A significant supercell thunderstorm developed southwest of Moree late on the morning of Friday 29 January 2016. At 11:00 am the storm had matured proceeding to make a left-shift in its course, a clear sign of its severity. The Moree radar images captured at 11:20 am, 11:30 am & 11:40 am show a clear hook echo. It is within this period with which the supercell has the hook echo that it passes over Millie.

See : 128km Radar Loop for Moree, 23:00 28/01/2016 to 03:00 29/01/2016 UTC


Millie, NSW

The damage documented at Millie is limited in pictures to one property. The degree of damage done to the prefabricated home (MHDW) is indicative of winds in excess of 100 km/h. The damage pictured shows no indication of tornado activity at Millie, the damage is consistent with straight line winds.

Storm damage following a supercell that swept across Millie on 29th January 2016. A team of 6 volunteer members from...
Posted by NSW SES Narrabri Unit on Friday, 29 January 2016


As the supercell passes southeast of Moree in interacts with a developing storm approaching from the north. The storms crashed into one another sapping their intensity.

Warialda

As the cell regenerated it continued over Warialda. As it passed east of the town it produced distinctive damage to a forested area. One local posted "Trees thousands of them torn out or stripped to the point where we can now see Gragin peak." sharing images of the carnage.

Every tree stripped to the point you can now see Gragin peak
Posted by Jenny Wren on Wednesday, 3 February 2016


The unique pattern of damage evident in the picture below is typical of a tornado. On close inspection the trees have been felled in multiple directions. Significantly, trees on the left of this picture have been felled towards the right, while on the far right of the image we can see a tree has fallen towards the left. This convergence of damage is clear evidence of a tornado being the responsible weather phenomena in this event. The degree of damage to the area of forest pictured is consistent with winds in excess of 145 km/h (expected winds of 175 km/h) equating to a tornado of EF1 intensity.


Image Credit: Jenny Wren, shared with Higgins Storm Chasing (Facebook).

Warialda Tornado - 29/01/2016

Sunday, 31 January 2016

At least two tornadoes touched down in Forbes Creek, NSW and Reservoir, VIC on Saturday 30 January 2016, with a possible third tornado occurring at Palmers Island, NSW.

Forbes Creek, New South Wales.

Damage shown in pictures and videos indicate winds consistent with EF2 intensity tornado. The video posted by Stormspotters AU (below) shows large areas of EF1 damage. There are three damage points that are indicative of an EF2 tornado in the video. At 4'35" the house has lost large sections (if not all) of its roof structure, but most walls remain standing. This degree of damage to family residence indicates winds 165-225 km/h with an expected intensity of 195 km/h. At 4'38" and 9'40" two separate hardwood trees appear to have been partially debarked. This degree of damage to a hardwood tree indicates winds 195-265 km/h with an expected intensity of 225 km/h.


Damage detailed in articles by the ABC and Sydney Morning Herald show the same degree of destruction to a second family's home. These four points of evidence (particularly the structural damage) lead to the conclusion that the winds contained in this tornado peaked at about 195 km/h.

The home of Geoff and Jan McKergow at Forbes Creek was all but destroyed by Saturday night's storm.
ABC News: James Fettes

A map showing the damage path tweeted by Queanbeyan City RFB show a trail of destruction approximately 3.75 km long, with reports that the path was approximately 100 meters wide.

Image Credit: Queanbeyan City RFB.
Tornado damage path Forbes Creek, trees felled in multiple directions. Image credit: Queanbeyan City RFB.
Canberra (Captains Flat) Rain Rate Radar 23:36 EDT 30/01/2016 - arrow indicates dip in radar intensity.
Base Image Credit: weatherzone.com.au
Canberra (Captains Flat) Rain Rate Radar 23:36 EDT 30/01/2016 - line indicates interpretation indicating potential hook echo around dip in radar intensity. Base Image Credit: weatherzone.com.au

The Canberra (Captains Flat) Doppler Radar shows a mesocyclone passing directly over Forbes creek at 11:36 PM (23:36 EDT). This is accompanied by a potential hook echo that can be observed on the Rain Rate Radar image at the same time.

Canberra (Captains Flat) Doppler Wind Radar 23:24 EDT 30/01/2016 to 00:06 EDT 31/01/2016 - arrows indicate mesocyclone. Images chronological left top to bottom then, right top to bottom at 6 minute intervals.
Base Image Credits: weatherzone.com.au

Reservoir, Victoria.

As reported by 7 News Melbourne, a tornado impacted parts of Reservoir on Saturday night. Damage in pictures of the aftermath indicates the tornado was of at least EF0 intensity, packing winds in excess of 100 km/h.

Melbourne Radar, Rain Rate 23:24 EDT (left) and Doppler Wind 23:25 EDT (right) 30/01/2016
Circles indicate possible hook (left), and the mesocyclone (right). 
Base Image Credit: weatherzone.com.au

Doppler radar shows a mesocyclone and possible hook echo passing over the area at the time that CCTV footage (7 News Report) shows the tornado impacting the area at 11:24 PM (23:24 EDT).

Palmers Island, New South Wales.

The damage at Palmers Island is indicative of at least an EF1 intensity tornado, but as no images of the actual tornado exist, nor is there a high resolution Doppler Radar in the area to provide evidence to support the hypothesis, it is probable that this was a tornado but can not be confirmed. Damage indicates winds of at least 165 km/h.

Storm damage at Palmers Island, NSW Coast. ABC: Debrah Novak
Wind speeds in this post are conservative estimates calculated from the damage observed using the Enhanced Fujita (EF) Scale.

Tornadoes in two states 30/01/2016

Monday, 11 January 2016

Rarely do I reflect on the joy that playing the tuba well brought me. The flutter of the pistons under my fingers. The faint humming sensation of damp numb lips as postlude to prolonged practice. But those days are long since gone, along with all of the skill I once had. Before my tuba memories fade further its seems logical to record as much as I can.

As an eight-year-old I had the opportunity to join the school band. As a teenager I considered these musical institutions as one step up from the medieval torture of a thousand recorders being piped by primary pupils in the Sydney Opera House.

The primary school was lucky enough to have a full time music teacher. Each class would visit the music room once a week. A room containing an assortment of instruments; mostly the variety played by beating them. Xylophones, glockenspiel, triangles, bongos and various little drums were trotted out for our enrichment. It was in one such trip to the music room that the tuba first came into my life.

Sat cross-legged on well worn blue-grey carpet the class listened with varying levels of interest as the school's music teacher Mrs Borrow-Jones acted as our musical maitre d'. Flash cards with child-friendly cartoon pictures served as instrumental menu for second graders.

I can't recall much of what went through my mind as the options were laid out. Did I have a short list going? Was I tempted by another instrument? All I do remember is the moment when I saw the tuba. Words had yet to form in Mrs Borrow-Jones' mouth, but I knew that whatever this instrument was, whatever it was called, however big or small, high or low, it was the one for me.

Within days of this encounter my Mother asked, "So, which instrument do you want to play?"

I was stumped by this simple question. I knew the answer. I could see it in my minds eye, but what was it's name? After a moments pause I replied, "It's the big brass one."

"Which one David?" Again asked my Mother as she turned her head to see me on the back seat. Mum was driving, she was always driving us kids somewhere. Four of us, all under the age of ten.

"The biggest brass one," I replied again a little louder, searching for the word. "It starts with T." I said struggling to recall more information.

"Most of them do." I was reminded with a smirk and a raised eyebrow as the blind spot was checked. The clicking of the indicator tutting my poor memory.

I'd walked into that one. "Um... it's sort of round..." I said attempting to describe what was in my empty little head, "...and has a big bell."

"Round with a big bell. Are you thinking of the french horn?" Mum queried as we paused at some lights.

"No, it's bigger and starts with a T!" I emphasized, as only a child could.

"Alright," Mum said in a problem-solving tone, "Was it the trombone?"

"No." I uttered glumly as nothing more came to mind.

"The trumpet." Mum suggested earnestly as the lights changed.

"That's the smallest one." I said an octave higher, exacerbated by the loss of such crucial information.

"Okay David," Mum replied, accelerating across the intersection. "Just have a think about it," now shifting into second, "And tell me if you remember."

To be continued...

Forgetting Tuba - Part One