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.


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