[MungoJP]

For those of you interested in big storms in the Southern Hemisphere, I have found some interesting data about just how similar storms are on two different continents. The coastal escarpments of both East Australia and East S Africa both act like drylines with offshore breezes provinding the inflow which is then ramped up, while troughs coming off the southern ocean provide the instability...

 

Exhibit A a massive 3 hour storm that hammered Sydney and thereabouts.  

http://www.bom.gov.a...april1999.shtml

Exhibit B another massive storm in KwaZulu-Natal that put down a 120 km long F4 that did big time damage. 

[P.K.]

Without looking at the page for the Sydney hail storm I believe it was the costliest natural disaster in Australia. There is more on it here. 

[MungoJP]

Same site. Wasnt the 1970's Darwin Typhoon the costliest? Forgive me, don't know much about Australia. Anyway it's one big storm travelling right over the most populated areas of NSW in one night, no wonder.

[P.K.]

Darwin is far smaller than Sydney population wise though so I believe Severe Tropical Cyclone Tracy actually caused less damage as there was less to damage. Also Tracy was very small, the pressure gradient was of the order of 4.5hPa per km in the centre. The link I posted says "The severe hailstorm which struck the eastern suburbs of Sydney on 14 April 1999 caused extensive damage which has been estimated of the order of $1Billion, making it possibly Australia's costliest ever natural disaster." However Larry was also initially estimated at AU$1 Billion so we'll have to see what happens to that figure. Other BoM pages however list the Sydney hail storm of 1999 at higher than AU$1.5 Billion.

[MungoJP]

Ok thanks. Pretty damaging for a supercell that hasnt even produced a tornado.

[StephenS]

My ex-stepdaughter (I suppose one can have ex-stepdaughters in these divorce-prone times) was in Sydney and slept through the whole thing. As she would almost certainly have said, how cool is that? D-) [c] Personally, I was devastated not to have a first-hand account! o| :'(