HISTORICAL CYCLONES & CYCLONE TRACY which destroyed Darwin xmas 1974/5. Information on cyclone tracks, history, structure. Photos and data from previous cyclones and yearly stats!


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TC Tracy 1974-5

 

Link to Bureau of Meteorology Darwin for cyclone information and current cyclone status here:

http://www.bom.gov.au/weather/cyclone/index.shtml

The bureau has just released its new naming format for cyclones including the first name which will be allocated this season if a cyclone forms. You can view all the new info here:

http://www.bom.gov.au/weather/cyclone/about/cyclone-names.shtml


DARWIN & TROPICAL CYCLONES. 

 

Darwin has experienced many near misses and in April of 2006, late at the end of the wet season when everyone thought the monsoon had gone, TC Monica staring off the Queensland coast initially as a category 1 cyclone, but did an abrupt U-turn and tracked back towards Darwin and was soon rated category 5 once in Territory waters and headed for Darwin threatening major damage and in fact caused significant damage to some areas.

 

CYCLONE  STRUCTURE:

 

Cyclones, hurricanes, typhoons - they are all the same types of systems except that in the northern hemisphere they spin counter-clockwise and in the southern hemisphere they spin clockwise.  Their destructive forces remain unchanged, they are all massive storm systems and only tornadoes rival them in power. They are the most destructive systems on the planet..

 


 

( courtesy of http://www.aerospaceweb.org/ 




 

Cyclones around the tropical north of Darwin typically require warm waters for energy.  Developing tropical lows favour waters in the range of 27c and usually are imbedded in monsoon troughs with good northwesterly monsoonal inflow winds.  Their life cycle can take up to a week to develop into cyclone category (see table below) and can last several weeks if conditions favour development over favourable winds and ocean temperatures.
 

 Systems within our tropical north are very erratic in movement and monitoring them by the weather bureau is an ongoing task.  You may have seen hurricanes take a predictable path, but cyclones here twist, do U-turns, hook, reverse back to original paths and are very unpredictable at a moments notice and pose serious threats if flash advices are issued due to their movement.

 


 

( low pressure systems with 'triple point' character or cyclogenesis)


CYCLONE SAFETY.


Cyclone awareness is your first defence with living with cyclones.  Have a well stocked first aid kit, torch, batteries, radio, waterproof plastic bag with warm clothing and also light clothing. Running shoes - forget the high heals ladies! Toiletries and hygene essentials in a plastic bag.  Have a well stocked food tub with canned food, powdered milk etc and essential opening devices.  Large container(s) of water. Keep pets inside the house with you or in a solid sheltered area.  The Northern Territory News, Police, Fire and Emergency services and insurers print booklets about what to expect and do during the cyclones season so check them out.



Securing your house.  Do that big clean up well before the cyclone season starts.!  Tie down anything you think can't and can be blown away - the trampoline, swings, dog house, push bikes and the like.  Don't be fooled into thinking something weighing 100 kilos can't be picked up and flung across into your neighbour's front door.  It can and it will.  Cyclones produce sustained winds and wind gusts in excess of  the forecast wind speed.  I've found tops of mature palms in my back yard during severe storms with 90km/h winds - they did not come from my garden or both my neighbour's gardens!

Taping your windows in all reality won't stop anything traveling at 100km/h.  It only takes one projectile to break that window and the rest can be blown out and be hit with other debris.  Do it if you feel more secure, but if the worst does happen,  you and your family's safety is the most important thing. Close the windows and shut the curtains and stay away from theses areas.  Opening windows on the lee side of the wind is useless and does nothing.  Pressure inside the house is not dependent on what window is open - the storm itself will have enough low pressure and an open window just lets wind and rain inside.


The storm will have two wind profiles - as cyclones spin clockwise you'll get wind from one direction and then a calming from the eye as it passes and then similar or stronger winds from the other direction.  DO NOT go/remain outside - stay inside and wait until radio announcements tell you the storm has passed or you are confident the second portion as eased. Remain calm until the storm has moved away.  You'll still get strong winds after and rain - but remember there's lightning around also and that's probably a reason to stay inside until safe to go out. 





 

(NOAA TRMM rainfall rate for

Hurricane FRANCES)


Cyclones are a massive collection of thunderstorms that group together around a low pressure system and continuously dissipate and regrow.  The images you see on satellite photos of the swirling rain bands are high level based cloud that is dispersed from the top of these storms, hence making identification easier. Imagine these systems as a thunderstorm - drawing in an energy source (warm water), dissipating what it does not require out the top of and regenerating off other storms and continuing this cycle repeatedly.  Winds are most severe towards the eye wall and ironically within the eye wall it is calm and blue sky often is seen from top to bottom. Once the eye is visible this is a good indication of favourable and strong development of the system. 


(cyclone and hurricane track paths over the years..NOAA pic)

lightning distribution map

 

 

As the chart further below indicates central pressure plays an important part of the strength of the cyclone.  Uniformally once the system reaches below 1000hpa and winds exceed a certain rate then it is rated as a Category 1 cyclone and named.  A cyclone can increase or decrease in intensity at any time during it's cycle, but moreover strengthens whilst still over warm water where it draws its energy source from.


(Hurricane Dean 2007 CAT5 Infra red image by NOAA) 


Central pressure may indicate strength but it can sometimes mask its true power.  There have been cyclones that have affected our coastline with higher central pressures but have caused more damage.  Structure of the cyclone plays a major role in how much punch it carries. 

For example, you could have a massive cyclone width wise with a low central pressure but not produce much damage or a very small, tight cyclone with also a low pressure centre but can cause massive damage. 

 

   

Many systems bypass Darwin.  Cyclones are favored by easterly steering winds and most often track across the Northern Territory coastline and away down to western Australia as the map displays.  More often than not cyclones that track across Darwin's northern waters continue to progress in a west, southwesterly direction towards the Western Australian coastline. 

(

 
 

 

As with the Fujita tornado damage F scale and the revised EF scale for prefixes for tornadoes (F3 or EF3 for 'Enhanced Fujita), cyclones likewise are being considered for re-classification dependant on maximum wind speed even to the point of categorizing them as Cat6 or supercyclones.

 Of course global warming and changing weather globally would have this effect of re-classification.  It is without a doubt that storms are becoming more violent and more regular as years go on. Tornado Alley to date (April 2007) has experienced 78 sighted tornadoes to date.  Surely something is going on in the atmosphere!

   

        Below is a 3D animation graphic of the structure of Hurricane Katrina.   Compare the actual satellite photo to see where the most active parts of precip are- red being most severe, ranging from blue to white for precip of less severity.





Cyclone Tracy - Darwin's

 

destruction on Christmas

 

day



After surviving Japanese bombings during WW2, severe tropical cyclone Tracy came along years later and totally destroyed our beautiful tropical city.  There are many stories to be told and I have included a link to one in particular that describes the ordeal perfectly.  I'm sure you'll find it fascinating yet be sympathetic to the helplessness the residents must have felt during the savage storm.  The link is below.


http://jennex.id.au/cyclone_tracey   


I also recommend you read Gary McKay's book entitled 'Tracy, the storm that wiped out Darwin on Christmas day 1974' available through good book shops or online at http://allenandunwin.com  This book is by far the the closest account you will read about the cyclone, the residents and the courage shown by Territorians before, during and after the cyclone.

 



 

Cyclone Tracy, Christmas 1974

(text & photos courtesy of Australian Bureau of Meteorology)

 

 (NOAA IMAGE OF TRACY)


The year 1974 started with tropical cyclone "Wanda" bringing torrential rain and flooding to Brisbane. It ended with another major Australian population centre being devastated by a cyclone. If Maitland epitomised flooding in Australia, and Ash Wednesday or Black Friday, bushfires, then "Tracy" comes most readily to Australian minds when cyclones are mentioned.

By world standards, Tracy was a small but intense tropical cyclone at landfall, the radius of gale force winds being only about 50 km. The central pressure of 950 hPa was close to the average for such systems, but the winds were unusually strong. The anemometer at Darwin Airport recorded a gust of 217 km/h before the instrument failed.

"Tracy" was first detected as a depression in the Arafura Sea on 20 December 1974. It moved slowly southwest and intensified, passing close to Bathurst Island on the 23rd and 24th. Then it turned sharply east-southeastward, and headed straight at Darwin, striking the city early on Christmas Day. Warnings were issued, but - perhaps because it was Christmas Eve, and perhaps because no severe cyclone had affected Darwin in many years - many residents were caught unprepared. But even had there been perfect compliance, the combination of extremely powerful winds, and the loose design of many buildings at that time, was such that wholesale destruction was probably inevitable anyway. Forty-nine people were killed in the city and a further 16 perished at sea. The entire fabric of life in Darwin was catastrophically disrupted, with the majority of buildings being totally destroyed or badly damaged, and very few escaping unscathed. The total damage bill ran into hundreds of millions of dollars. Cyclone Tracey

The devastation inflicted on Darwin by cyclone "Tracy" in December 1974 (photo by Australian Information Services)

 

 


As usual in such disasters, many communication links failed, but enough survived to let the world know of the catastrophe, and relief measures were soon under way. An airlift involving both civilian and military aircraft was swiftly organised, while many residents chose to drive out. Within several weeks, three-quarters of the population had gone.

This was not the first time Darwin had been severely damaged by a cyclone: it was badly mauled in both January 1897 and March 1937. But as a result of "Tracy", much more attention was given to building codes and other social aspects of disaster planning. Darwin was rebuilt and now thrives as one of our most important gateways to Asia.


 

(photo courtesy of NT archives, Michael Besnahan NTRS 1974 photo #15)

(Satellite image of Tracy as she hit Darwin)



 


Cyclone Tracy tracked SW of Darwin for some days and most people thought that it would track away from Darwin (as cyclones normally do here.)  Darwin had had a scare with a previous cyclone some weeks prior to Tracy so the attitude was that this one would divert away also - perhaps complacency set in!  However, closer to xmas day the cyclone made an abrupt left hand turn directly toward Darwin and the situation was dramatically changed for the residents.  Her wind speed and compact size added to her strength and the fact that she maintained her slow movement over Darwin for some hours before becoming a rain depression compounded the damage factor.

In retrospect Darwin has had a few close calls, especially in 2006 with Monica.  The question is not if we'll get another severe cyclone that hits Darwin but when.  We may not get the majority but it will only take one or two big storm to nudge near us again and who knows how things will sustain the winds.

 If you are visiting Darwin whilst storm chasing I would highly recommend visiting the NT Museum and Art Gallery.  They have a section on the cyclone and with the only TV news footage from ABC Television of the disaster, photos, and a unique dark room where you can listen to the cyclone's winds as it smashed through the suburbs that morning.  Many local residents who came through the cyclone won't even go near the audio room for obvious reasons.  Many local residents can tell you stories of fear and disbelief when the storm finally passed.

 

 

A wonderful site by the Northern Territory government and the NT Library on Cyclone Tracy can be found  here  http://www.ntlib.nt.gov.au/tracy/advanced/cyc_tracy.html


 Below is what was left of one of the suburbs in Darwin after Tracy.

 

 




BELOW IS SOME DAMAGE PHOTOS FROM TRACY FROM VARIOUS AID AND GOVERNMENT DEPARTMENTS.


power ole twisted by cyclone 

    


     

     


 

OTHER CYCLONES THAT HAVE

COME CLOSE TO DARWIN

 


Monica CAT5 April 2006

 

 



(summary and rainfall graphics courtesy Australian Bureau of Meteorology)

Severe Tropical Cyclone Monica caused significant impact on the Australian coast in April 2006. It crossed the Queensland east coast south of Lockhart River as a Category 3; moved into the Northern Territory and impacted on the small islands north of the Arnhem Land coast as a Category 5; before finally making landfall on the northwest Arnhem Land coast, just 35km west of Maningrida as a Category 5 cyclone.

Monica was a small cyclone in size, but very intense, not unlike Cyclone Tracy that devastated Darwin in 1974. For this reason, communities more than 100km from Monica's path (like Nhulunbuy) were affected only slightly. Generally, large rainfall

 

totals were experienced within 100km of Monica's path, however some of the largest totals (eg 261mm in 24 hours at Kidman Springs in the Victoria River District) occurred long after Monica made landfall, and was a weakening tropical depression overland in the Northern Territory.

Despite the widespread impact area of this cyclone, and the wind strengths experienced, there have been no reports of serious injury or death in Australia. Also, as the communities had all received good warning, much preparation, including the clearing of loose materials around the populated areas, reduced the final damage toll.

 


Track

(see map below)

 

On 16 April a tropical low developed just to the east of Papua New Guinea, and began to drift southwest into the Coral Sea. It developed into a tropical cyclone on 17 April, and took a more easterly track towards the north Queensland coast. TC Monica continued to develop as it approached Queensland, and crossed the coast just to the south of Lockhart River, as a Category 3 cyclone, on the afternoon of 19 April. It crossed Cape York Peninsula into the Gulf of Carpentaria on 20 April, temporarily weakening over land, but gathered strength rapidly once over water again. It then moved slowly towards the northwest, before starting a more westward track along the northern Top End coast on 23 April. It continued to travel along the north coast, before turning to the southwest on 24 April, and crossing the coast just 35km west of Maningrida in the early evening as a Category 5 cyclone. Shortly after landfall, TC Monica began extremely rapid weakening, and by the time it passed through Jabiru only 9 hours later, it had weakened to a Category 2 cyclone. At this point the cyclone began to track in a more westward direction towards Darwin, but weakened to below cyclone intensity only 3 hours later.



.

 

Impact

The cyclone crossed Cape York Peninsula at a remote location, avoiding the local townships of Lockhart River and Coen.

Communities along the north coast of the Northern Territory were not so lucky. Widespread tree damage and moderate damage to infrastructure was reported along the Arnhem Land coast, extending as far west as the township of Jabiru. The automatic weather station at Cape Wessel suffered significant damage as the cyclone passed directly over-head as a Category 5 system. Maningrida community received substantial damage as the cyclone passed just to the north of the township, with several houses damaged by fallen trees. The uninhabited coastal crossing point, just 35km west of Maningrida, suffered severe vegetation damage, with 50%-70% of all trees felled, as well as evidence of a 5-6m storm surge zone in Junction Bay. The cyclone weakened rapidly as it moved inland, however Jabiru still experienced some damage, mostly due to fallen trees. Darwin was spared the major wrath of the cyclone, with gusty winds and rain only causing minor problems with unstable trees.

As the low tracked southwards through the Top End and Victoria River District, heavy rainfall caused major flooding in the Adelaide River catchment, as well as moderate flooding in the Daly, Katherine and Victoria River catchments.

 





Maximum Reported Wind Gust
109 km/h gust at Lockhart River, 3pm EST 19 April
130 km/h mean wind at Cape Wessel, 8pm CST 23 April
148 km/h gust at Maningrida, 6:40 pm CST 24 April
118 km/h gust at Jabiru, 3:02 am CST 25 April

Lowest Reported Pressure
986.0 hPa at Lockhart River
970.2 hPa at Cape Wessel
986.2 hPa at Maningrida
986.6 hPa at Jabiru Airport

Rainfall - Queensland
215 mm at Lockhart River in the 24 hours until 9am on 19 April.
239 mm at Violet Vale in the 24 hours until 9am on 20 April
282 mm at Musgrave in the 24 hours until 9am on 21 April

Rainfall - Northern Territory
190 mm at Ngayawili in the 24 hours until 9am on 25 April
340 mm at Majestic Orchids (near Darwin River Dam) in the 24 hours until 9am on 26 April
261 mm at Kidman Springs in the 24 hours until 9am on 27 April

East Coast Landfall Parameters
When: 3:30 pm EST 19 April
Where: 40 km south-southeast of Lockhart River
Severity Category: 3
Estimated Maximum Wind Gusts: 200 km/h
Estimated Central Pressure: 960 hPa
Estimated Storm Surge: 3 metres
Eye Radius: 19 km
Radius of Maximum Winds: 20 km
Radius of Very Destructive Winds: 20 km
Radius of Destructive Winds: 35 km

NT Parameters

Day

23 April

24 April

25 April

Time

9:30 pm CST

8 pm CST

3:30 am CST

Where

Cape Wessel

35km west of Maningrida

Jabiru

Severity Category

5

5

2

Estimated Maximum Wind Gusts (km/h)

360

360

130

Estimated Central Pressure (hPa)

919

917

983

Eye Radius (km)

15

17

19

Radius of Maximum Winds (km)

19

22

28

Radius of Very Destructive Winds (km)

46

37

-

Radius of Destructive Winds (km)

74

55

30

 

Rainfall

The maps below show rainfall during the week ending 23 and 29 April 2006 respectively. Figure 1 shows the effects of Monica in Queensland, while Figure 2 shows the effects on the Northern Territory.






 

(Monica tracking West toward Darwin from the east)




 

Monica was strong enough to sustain a Category 4 rating even though half of her mass was over land and over sea.  This will make for some interesting studies as to her structure whilst making landfall and what conditions she was in.  Darwin was very lucky to escape this cyclone and interestingly, Darwin City only received minimal rainfall as she passed us to the south - ironic!  Her structure was perfect as the photo shows, well defined spiral bands, strong circulation, prominent eye indicating strong inflow.





 

Tropical cyclone George CAT4


During the 2006/07 cyclone season I was monitoring a tropical depression for some weeks as this system moved toward Darwin. It had tracked somewhat predictably toward Darwin as most of them do and then track more westerly away and around our coast over to Western Australia.  That particular day I had left my camera at home (which I normally never do during the wet season) and noticed that the atmospheric sounding for that morning was showing some fabulous numbers.  The CAPE find out about CAPE numbers were through the roof and the Lifted Index or LI find out about lifted index numbers , this all means that that day was going to go insane for storm activity.  Seeing that pre-cyclone George was close and about to pass over Darwin on its way  deepening to a tropical cyclone my heart was heavy as I heard rumbles and noticed lightning outside our office window.  Fortunately for me my office has a harbour view and city view and I was becoming increasingly depressed at what I was about to witness with no camera in hand!


By lunchtime the tropical low was passing over Darwin and I counted over 6 lightning strikes per second over the city, as I looked over the ocean fantastic close strikes smashed the ocean and the buildings and all I could do is curse for not having my camera. In a 2 hour period there was over 3000 lightning strikes in the city and suburbs.  The CAPE had gone from around 2400 j/kg to over 3800 j/kg or higher and the lifted index was -8!!  Oh my God!  Just in case you're totally confused; high CAPE values and negative or minus LI numbers mean great storms in Darwin - basically it means the more instability we have the better...


I watched lightning just flash all over the place and on the fourth floor balcony at work it was just an awesome display of power.  If a developing cyclone is like this then there is definitely something to be concerned about one's safety if it developed into a full-blown cyclone..I vowed never to leave my camera at home from that day forth!

Severe Tropical cyclone George sadly took some lives and injured many more as he crossed the WA coastline some days later as he ventured into warm waters off the WA coast and then tracked into Port Hedland.





 

(The following details are from the Perth region of the Australian Bureau of Meteorology)


Severe TC George was both very intense and physically large. During the event, gales were reported on or near the coast as far north as the Northern Territory border on Sunday 4 March as the cyclone moved across from the NT, and as far west as Karratha on Thursday 8 March. The cyclone intensified to a Category 4 system as it approached the coast, but post-analysis may indicate intensity of Category 5 at landfall.
 
The wind impact was greatest between Wallal and Whim Creek with a mean wind of 195km/h (equivalent to gusts of 275 km/h) being recorded offshore at Bedout Island. At Port Hedland Airport, gusts of 154km/h were recorded around 10:30pm prior to equipment failure. It is likely that stronger winds were experienced around midnight, on the edge of the very destructive core.

TC George produced large amounts of rainfall in the Northern Kimberley and the Northern Territory earlier in its lifecycle, before moving offshore and intensifying into a significant cyclone. Upon approaching the Pilbara coast, substantial falls occurred, however the lack of previous rainfall limited the potential for flooding. No significant flooding was recorded.

Port Hedland escaped direct impact from storm surge as the cyclone passed to the east of the town.

Reported impacts include three fatalities and numerous injuries at mining camps south of Port Hedland. Considerable damage was reported from Port Hedland with at least 10 houses losing roofs, despite solid construction practices in the Region. The Bureau's Port Hedland radar dome was damaged.

Tropical Cyclone George was the most destructive cyclone to affect Port Hedland since TC Joan in 1975.



Coastal Crossing Details
Crossing time: 10pm WDT Thursday 8 March 2007
  50km ENE of Port Hedland
Category when crossing the coast: 4 (to be confirmed on post-analysis)


Extreme values during cyclone event (estimated)
Note that these values may be changed on the receipt of later information
Maximum Category: 4 (to be confirmed on post-analysis)
Maximum sustained wind speed: 195 km/h
Maximum wind gust: 275 km/h
Lowest central pressure: 910 hPa