Topic: Ten Years Since The Great Sydney Hailstorm!

[Steven]

Ten years ago today marks the anniversary of the Sydney Hailstorm which resulted in Australia's costliest natural disaster. Now I actually grew up in the eastern suburbs but I left way before this occurred and that suburb was one of the hardest hit from what I hear. I was actually in the area last week and it crossed my mind but I didn't ask. Had I been living there at the time, I don't think I would remember much.

I think Michael and Jimmy might remember this because it is in the archives on the site. I've cherry picked some interesting passages in the Wikipedia entry.

* The 1999 Sydney hailstorm was the costliest natural disaster in Australian insurance history.
* The storm dropped an estimated 500,000 tonnes of hailstones in its path.
* Insured damages caused by the storm were over AU $1.7 billion and AU $2.3 billion in total.
* Approximately 24,000 houses were significantly damaged, with many suffering water damage.
* The stones were estimated as travelling at up to 200 km/h (120 mph) in some periods of the storm, causing indentation damage to around 70,000 vehicles.
* Roughly 62% of buildings in the affected areas suffered damage to roofs, around 34% to windows and 53% to vehicles.
* In total, the State Emergency Service received 25,301 calls for assistance to 15,007 incidents.

I'll leave the technical analysis to the experts around here. What caused it? Why did it happen? Why did it affect Sydney so badly?

[Jimmy Deguara]

Steveo,

Yes it was one hell of a supercell. As I have hinted in the past, this one was made worse in my opinion by a second severe storm possibly a supercell that tracked almost along the same path of the first. This storm dropped golf ball sized hail and was reported by quite a few news stations as 'the storm'. It's link to the dame is your reference to the water damage whereby much of the internal damage may have taken place that normally other supercells would not have done so on their own.

The first supercell though did most of the initial damage - holes through the predominant slate tile roofs, smashed windscreens in cars and also house and building windows. Some of the damage was saw in our survey a couple of days after were significant. Cars were almost pulverised indicating hailstones in the order of 11 to 12cm diameter.

The storm took most by surprise because few if anyone picked up on the short wave upper trough sneaking up the coast creating an environment of significant destabilisation. The temperatures were relatively warm for April and there was a sufficient cap in place to assist in suppressing the energy. Added to all this was a steady moist NE airflow into the storm environment and this combined with the SE change to provide a trigger. All in all, it created an environment that exploded during the later afternoon and then evening hours. The initial storm cell developed in the Illawarra and tracked the coastline. It's rapid development and backbuilding as Michael Thompson observed and reported backed up by my observations and others of a major steep flanking line whilst it was off the coast sent it onshore over the Royal National Park. This put it in a position with such a sharp deviation to set a course towards the airport and then the Sydney eastern and southern suburbs. I guess it dumped its load over this region creating most of the significant damage. A new updraft developed and headed towards the Northern Suburbs with golf ball sized hailstones reported.

Where was I in all of this? I was attempting to turn my life around - a new beginning trying something different and went to my first meeting at a bush walking club. A 2 hour meeting whilst Sydney was being pulverised. That was my first meeting - and last!

Regards,

Jimmy Deguara

[Michael Thomas]

Amazing to think that it has been 10 years. I can still remember the storm clearly though it does feel like quite a long time ago now. I watched the storm approach before it crossed the coast north of Kiama. Quite spectacular watching it and I still remember one large bolt in particular coming down and pulsing. Most impressive though was the quantity of hail. The hail was only small at that stage luckily but the roar of so much hail falling is quite an experience. I can only imagine what it would have been like in Sydney.

[Michael Bath]

Here's a couple of links:

http://australiasevereweather.com/storm_news/1999/docs/9904-01.htm

and the Aussie-Wx discussion list archives:
http://australiasevereweather.com/storm_news/list1999.htm

Check the 14th April and the following few days for comments.

MB

[Richary]

I was living in Gosford at the time and saw the flashes to the south. Should I put the car away - no won't worry, it's a long way off.

Next morning woke up to hear of the devastation. At the time I was on contract for Telstra in the city and purely by chance had to go to Paddington to change the backup tapes. I decided to walk up there, and as you walked up the road on one side every windscreen was smashed and on the other, every rear window. With the cars looking like someone had taken to them with a large ball hammer.

Once at Paddington I went onto the roof, at 5 stories the exchange is the tallest building around. Every slate and tile roof visible just had massive holes in it. A colleague who lived at Eastlakes had just finished 2 years of internal DIY renovations to the house, all of which were wiped out by water damage from the holes in the roof. His comment was that well now insurance can pay someone to do it properly!

[Robert1984]

If i can remember didnt the Weather Bureau got into alot of trouble cause they cancelled that severe wx warning for Sydney thinkinkg the storm wasnt intense enough then the supercell popped up causing mass damage and destruction on a wide scale before they could re-issue the warning

[Michael Thomas]

Robert,

If you are interested I suggest that you read the following report-

http://www.bom.gov.au/inside/services_policy/storms/sydney_hail/hail_report.shtml

It gives some quite detailed information on the meteorological conditions, storm characteristics and also the performance of the BoM with regards to issuing warning.

Severe storms producing gaint hail are quite rare during April for the Sydney area. Also, storms usually decrease in intensity after sunset due to cooling surface temps (reduced CAPE and increased CIN). Therefore, a storm of that intensity is quite amazing and just was not expected. I would have to say though that it would have been clear that the storm was a left-moving supercell. With the reports of large hail to the south of Wollongong a warning should of, and probably could have, been issued. Hindsight is 20/20 and if there was a warning out I doubt that it would have made much difference.

[Jimmy Deguara]

Michael,

I would not beat around the bush myself trying to be politically correct. The Bureau stuffed up on this day and to my knowledge did not react to issue warnings until it was too late. In fact, I was told that at 7:00pm ish, the lastest forecast was chance of an isolated shower. Yes a shower of monster hailstones. And when the media call you and ask why there isn't a warning and that they have been inundated with calls by callers on talk back radio, then I would definitely look into issuing warnings.

Whether it made a difference or not is not the issue - the warnings should have been issued and there should be meteorologists trained sufficiently at any time to issue a warning based on the severity of the radar. Well we storm chasers did!

I really found quite funny but quite fitting for the event a cartoon depicting the Bureau building being bombarded and amshed in by giant hailstones and a person on the phone suggesting "anyone hear anything about a hailstorm?"

Regards,

Jimmy Deguara

[David C]

Michael Thompson's report is a very good read too >> http://www.ozthunder.com/chase/chase13.htm

That was a night to remember. I was at home at the time. As it moved over Beacon Hill the stormed seemed to be reorganising. By that I mean after trashing the inner city it did seem to weaken somewhat on radar (RHI scans in particular show lowering if severe echo tops). We had hail to around 3cm at best, and then a period of some vicious CG lightning. The storm then soon went on to produce more very large to giant hail and some wind damage as it tracked further north along the northern beaches and towards the central coast.

I had work colleagues at Coogee in Sydney who survived the first storm unscathed, but then suffered hail damage to their cars due to very large hail from the second storm.

[David C]

Michael,

I would not beat around the bush myself trying to be politically correct.

and

Where was I in all of this? I was attempting to turn my life around - a new beginning trying something different and went to my first meeting at a bush walking club. A 2 hour meeting whilst Sydney was being pulverised. That was my first meeting - and last!

Regards,

Jimmy Deguara

Sorry Jimmy I just could not help myself I know that one hurt hehe

[Michael Bath]

I found that cartoon in my archives Jimmy - yes it is a classic

MB

[synopig]

Yes I remember watching the storm approach from my  7th floor apartment in Randwick with 270 degree views, north thru west.
Most memorable was one huge rouge hailstone that had been spat out well in front of the storm.

Illuminated by ground lighting, I watched this thing hurtle down thinking WTF is that. About 3 seconds after it disappeared into suburbia, there was a huge BANG. I knew then we were in trouble. This heralded the forthcoming onslaught, which minutes later sounded like thousands of stampeding horses.

What a night to remember....

[Jimmy Deguara]

Do you or anyone have pictures or videos from this specific event? There is only one piece of footage from an appartment from the FIRST main storm event (media have ample coverage of the second storm). The footage displays hailstones the size of house bricks falling in a swimming pool! And the noise was incredible too!

Regards,

Jimmy Deguara