Author Topic: Tropical Cyclone Helen - NT: Jan 2008  (Read 10619 times)

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Offline Mike

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RE: Tropical Cyclone Helen - NT: Jan 2008
« Reply #15 on: 06 January 2008, 05:22:55 AM »
TC Helen chase report 5 January 2008

Summary:

TC Helen made landfall between 11pm and 1am on Friday morning near Port Keats to the southwest of Darwin.  Its structure was a little weaker than I had expected given its CAT2 status.  Rain bands were very widely spaced and the only major lightning was to the SE and NE of the actual system.  The NE sector produced a lot of lightning for the first 3 hours as the convective band swept across the areas of Cape Don and Black Point some 400km away.  I suspect that her entering a landmass had hindered her efforts to gain further strength and she was moving quite quickly between 16-20kts for most of her journey towards the NT coast. 

There was no distinguishable eye throughout her movement on radar or satpics, the rainbands circulating around the centre were wide and seemed to detach somewhat from it.  Given more time and more ocean she would have definitely gotten more organised.  From about 5am there was little or no rain to speak of, although Batchelor and Adelaide River would have borne the brunt of the central winds of 130kmh as the 'eye' passed directly over Adelaide River which is a township around 90km to the SE.

Winds arrived in Darwin as she moved closer and she was only 180km away to the south of us.  Heavy squalls and rain lashed Darwin itself and consistent wind gusts accompanied them.  The winds lasted for approx 6 hours from 2am-6:30am when the there was only moderate winds and a graduall easing.  The system was approx 80km to the south at 7am and still a CAT1.  Observing the white low level clouds, they were just amazing to watch as they streaked across the sky under a blanket of blue/grey.  Their movement was so fast I could not keep up with them even driving at 80kmh!!!

Damage

I keep telling people up here that are pretty complacent (long time locals also) that even a CAT2 can cause serious damage.  Driving around in the early hours I could see major damage to some properties from very large Mahogany trees, which being shallow rooted and with the aid of two weeks of wet weather, really did cause the major damage as the toppled over.  Some of these trees were over 20m tall and just as wide - death traps in reality.  A strong band embedded with thunderstorm outflows aided the strong gusts in this area.

Powerlines were down in the suburbs Nightcliff and Parap.  Nightcliff sustained the most carnage.  Being right on the coastal areas it is open to stronger winds coming off the ocean.  Many trees were felled across the roads in this area and other areas towards Darwin that are on the coastal fringe also sustained lots of debris and felled trees.  Most traffic lights in the northern areas were out and i believe power was lost to most of the areas here also.

Surveying the damage I could not help to wonder what if this cyclone was stronger - CAT4 perhaps - there would be just chaos.  The trees that Darwin has are just minefields for damage to occur.  People still parked their cars on the roads next to big trees that were accidents waiting to happen! Trees in Darwin are large, old and really the wrong type whoever planted them.  Palms were all still standing, it was the gums, mahogany and other species that got flattened even with 100kmh winds on the coast.  I dread to think what would have happened if the winds reached 250+.

All in all a great chase experience.  A sureal sensation as one sits in the open hearing the relentless howl of the wind, knowing that it won't let up for a very long time until daylight.  The rain was nothing out of the ordinary, I've actually seen heavier falls with severe storms in Darwin, it was just coming in waves as you'd expect with the bands flowing through.

I hope I've given some interesting facts and accounts during the cyclone for members.

'When's the next one'!!!

* Photos of damage I will post here simply because the event is over and for simplicity of viewing members.  Am compressing them now to attach....


Mike


« Last Edit: 06 January 2008, 05:50:19 AM by Mike »
Darwin, Northern Territory.
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Offline Mike

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RE: Tropical Cyclone Helen - NT: Jan 2008
« Reply #16 on: 06 January 2008, 05:54:51 AM »
Some more photos.  Not too much structural damage to houses, but the ones that the big trees hit did so.  I'm sure there's some cars that got hit in other side streets considering the amount of large tree types that were pushed over.

Mike
Darwin, Northern Territory.
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Offline Jimmy Deguara

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RE: Tropical Cyclone Helen - NT: Jan 2008
« Reply #17 on: 06 January 2008, 08:02:25 AM »
Mike,

It certainly must be a case of large trees, wet and weight of water in leaves and soggy ground -the combination - uprooted trees. Still you have to have severe winds to do this much damage.

Regards,

Jimmy Deguara
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Offline Mike

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RE: Tropical Cyclone Helen - NT: Jan 2008
« Reply #18 on: 06 January 2008, 09:18:21 AM »
Indeed.  I've just been out for another drive-by sussing out the damage around the city - the coastal areas by far have been hammered.  The only other time I can remember whilst living here with this much damage to trees was TC Gretel way back in 84-85 and she also was a CAT1-2. 

 I told a fib earlier about no palms being uprooted - just found a 15 metre Cuban Royal palm upended onto a fence!!  These things are sturdy as and it has shifted 2 metres from where it was planted!  Insane stuff.

Honestly, anyone who lives in Darwin and is complacent about cyclones - especially CAT3-5's should think again how dangerous these winds can be from the amount of downed trees.  If Monica had hit last year in the cross-hairs on Darwin with 360kmh winds it would be a wakeup call to everyone here, the amount of damage would be terrible.


Mike
« Last Edit: 06 January 2008, 09:41:19 AM by Mike »
Darwin, Northern Territory.
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Offline Mike

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RE: Tropical Cyclone Helen - NT: Jan 2008
« Reply #19 on: 07 January 2008, 07:52:03 AM »
Last lot of shots that i took yesterday along the coast,  These trees were obliterated by the winds - BoM think some of the gusts may have been 140kmh near her centre - these trees were not uprooted, simply blown apart!  Helen is expected to form in the Gulf as a CAT1-2 cyclone again by Tuesday.  She's hiking along at a rate of knots just east of Gove now.

My favorite shot is the busted stump and limbs in the foreground to the proud palm still standing - kinda looks like a cathedral!

Mike

* some info just in via email courtesy Greg Browning, Severe Weather Section, Bom here in Darwin re Helen.  (it's Queensland's baby now they say!)

Extra details

Helen crossed the coast 130 km southwest of Darwin near Channel Point.

Channel Point Observers recorded 975 hPa at 10:47 pm Friday night, their maximum wind estimate was 60-70 km/hr.





At 09:13 AM 5/01/2008, Lori Chappel wrote:



TC Helen crossed the coast as a Category 2 last night (Friday night) near 10pm.

Gales were experienced at Charles Point lighthouse from 7pm to 4 am (8-9 hours), max wind gust 120 km/hr at 130am.

Darwin airport experienced gales intermitantly from 1030pm, then consistently from midnight to 3 am. Max gust 102 km/hr at about 2am.

Point Fawcett on the Tiwi Island experience gales briefly 9-10pm.

Rainfall in the Darwin area has been 30-50 mm ( 24 hrs to 9am Sat)

Highest rainfalls have been in the path of the TC, Adelaide River Township area and the Douglas Daly area have been 150-200 mm. ( 24 hrs to 9am Sat)

Kakadu (Jabiru, Central Arnhem) has recorded 100+ mm ( 24 hrs to 9am Sat)



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lori Chappel             
Weather Services Co-ordinator            Ph      (08) 8920 3810 
« Last Edit: 07 January 2008, 08:00:04 AM by Mike »
Darwin, Northern Territory.
StormscapesDarwin.com
Lightning Research 2010/14