Topic: Sydney hailstorm - 14th April 1999

[Jeff Brislane]

Southern or Western, either way window breakage was a much bigger problem in 1990 as compared to 1999. I don't know fully why but I would bileve that hail that impacts rooves on a flatter angle would tend to glance off more without damage. I have footage from 1999 which shows the hail falling almost vertically which given the size should account for more tile damage you would think than glancing blows.

Physics should proove that glancing hail transfers less energy on impact than directly hitting hail. Also 80% or more of rooves in Australia are built on a 22.5 degree angle which is relatively shallow. They used to build them at a 30 degree angle and i'd suspect that most of the homes damaged in 1999 had a 30 degree pitch.

[Jimmy Deguara]

I don't disagree Jeff. My point perhaps should have been made clear with more total damage on one or two faces of the roof facing more perpendicular to wind driven hail.

Regards,

Jimmy Deguara

[Geoff Thurtell]

There is a lot of evidence that the heavy rainfall in the second storm added significantly to the insurance claims. There was a woman working in the organics laboratory at AGAL at the time. She said that it was heatbreaking to see their slate tiles trashed by the first storm. She then described the despair that she and her husband felt when the second storm dumped more rain. Furniture, carpets, books and artwork which they thought that they had saved were water damaged during the second storm. She said that they simply did not have enough buckets and sheets of plastic to cover everything.

Over the next couple of weeks, I received quite a few phone calls from people concerned about possible asbestos contamination in the dust from their ceilings. Almost all of them said that their ceilings had held up until the second storm came through. It was the second storm that caused ceilings to collapse and cause extra damage to furniture and carpets that had not been damaged in the first storm.

I recall one person who was living in a converted factory with an asbestos cement roof. He said that the hailstones went straight through the roof and the ceiling. He also said that even with the hail damage, the second storm addded significantly to the water damage. Definitely that building had to have a thorough clean up of all of the dust before the residents were allowed to return, adding to the insurance bill.

Regards,
Geoff

[David C]

Good points Jeff - definitely some violent squalls with the 1990 storm.

Geoff, re second storm, I guess it is all academic.  I wonder how significant (ie %) the 2nd cell related costs were in the context of all other damage. Some coastal suburbs received larger hail with the 2nd storm but that was generally golfball sized from memory. As Jeff pointed out, repairs to damaged tiles and roofing would be substantial. There was footage of ceilings with fist sized holes.  Perhaps the influx of water was not only from the second storm but 12 cm ice rocks melting in the ceiling:-)

[Jimmy Deguara]

Hi David,

My thoughts were that the fact that full fledged storm with mostly precipitation and 4cm hailstones just through things over the threshold and contributed to the internal damage. That was my point - though I would be interested in some statistical breakdown.

Regards,

Jimmy Deguara

[Jeff Brislane]

Another interesting fact about the 1999 hailstorm was that the major insurance companys teamed up and leased a large industrial lot at weatheril park were most of the written off cars were taken to be auctioned off for parts ( or did the governmant do that? can't remember now). Also they caught a lot of people who had non-severe hail damage who had tried to write their cars off after the storm with sledge hammers! Apparently you can pick the difference between a sledge hammer and a 12 cm hailstone! 

I also recall seeing a near new sports car with a dent on it's bonnet so large and deep that the assesor could fit his fist into it and the impact had actually split the steel in the middle of the crater!

Another very expensive item that would have needed replacing is carpet. You could probably add another $10,000 per property just for that alone.

[Harley Pearman]

Sydney Hailstorm 1999

I was watching it from Granville and saw it move along the coastal suburbs. I remember telling Rita at the time before it unleashed onto Sydney that the storm was no ordinary storm. I knew it was a severe storm but I did not know enough about supercells at the time.

I note though that the damage insurance payout was $1,720 million putting it into the Gunness Book of World Records for costly hailstorms (Australian Section) after the event. It still ranks as far as I am aware, the worlds second most costly "hailstorm" after the Dallas - Fort Worth event of 1995 (Not sure what date) but damage from that was around $2 Billion. Amazingly Sydney Australia is up there and holds the Australian records for thunderstorms.

While on the subject of hailstorms and supercells, I pose this:- I am looking at what this season could bring in terms of Supercells for Sydney. I am intrigued that the corridor from "The Oaks to Hornsby" which is a well known supercell path has not fired properly for 4 years. The question is:- Is this ready to fire this year and produce a storm that will go all the way? I worked out, the Average return frequency is 2.66 years and looking at that, one would think that this path which has seen some big supercells would be ready to produce. It produced supercells in 1990, 1991, 1994, 2000, 2001 and last one February 16 2002. (The really big ones). I know there was a small one in late March 2003 but the whole storm collapsed around Seven Hills and did not go all the way. I am talking about something like 3 November 2003. Any discussion on this path as I am paying some attention to it? Thank you.


Harley



 

[Jimmy Deguara]

Hi guys,

Relating to the Sydney hailstorm on 14th April 1999, here is a Youtube video of the event with the smaller of the hailstones

http://www.videosurf.com/video/live-footage-huge-hail-smashes-city-4730198

Regards,

Jimmy Deguara