Author Topic: 5th August 1986 Floods - where were you?  (Read 15978 times)

0 Members and 1 Guest are viewing this topic.

Offline Jimmy Deguara

  • Australian and Tornado Alley storm chaser
  • Administrator
  • Wedge tornado F5
  • *
  • Posts: 2,218
  • Gender: Male
  • Storm Chaser since 1993, Tornado Alley 2001
    • Australia Severe Weather
5th August 1986 Floods - where were you?
« on: 02 August 2006, 01:00:08 PM »
Given we are approaching the an event in eastern NSW that resembles an onshore airstream with the potential of a rainfall event, I thought this is a great time to reflect on this significant event 20 years ago - the 5th August 1986 Floods. It was the first major flooding since 1978.

The August 1986 floods is an event that lives in the mind of any Sydney-sider who experienced it. You ask anyone - they may not know the date but when you remind them they say "yes - that's the one!". Now there have been other floods in this generation - but this particular event is astonishing given the record rainfall recorded in Sydney - 328mm in 24 hours in Sydney with regions in usually a much drier western Sydney exceeding the 250mm rainfall barrier.

Here is my recollection of the event:

I do recall my lift from school was late - very late in fact - I thought I had missed the lift. No matter which road he went through, the roads were impassible in the Toongabbie region. My brother on the other hand was 5 hours late arriving from the city by train. Although the rainfall during the day was very heavy, it was the constant drenching at night that had me awake finding it difficult to get to sleep. Not that I really cared. It was my first vivid major flood event having missed the 1978 major floods - I certainly was not going to miss the experience.

I do recall 4 consecutive days in late July being well above average - temperatures in the mid-20s followed by a very cold outbreak on the 25th July. Some regions in Sydney reported sleet with snow falling to low levels during the afternoon and evening. Two days later, I awoke to a severe frost. we had severe frosts that year but this one was exceptional - the rounded off temperature neared -minus 6 degrees Celcius making this the coldest morning in Sydney since the 1970 record cold temperature of -8.3C. By the way the maximum temperature warmed to 10C - well it is a 16C warming! It also rained which is why the temperatures remained low.

Not much seemed to occur until the 4th August when a thunderstorm occurred at Kurrajong with large hail. This was the beginning of the rainfall event. Rain continued on the 4th and became persistant. On the 5th August, the rain became heavy particularly during the day and evening. On the 6th August, besides some showers, the rain began to clear and the low pressure system that had 'bombed' (a term referring to the rapid development of a low pressure system) over eastern NSW retracted into the Tasman.

A tornado was also reported on the Central Coast on the 5th August probably close to the inner rim of the low pressure system. I suspect this may have been a waterspout making landfall. Another feature of this system was the strong to gale force winds though being inland, I did not experience these conditions. Tragically, the event claimed the lives of 4 people including two children swept away as the family tried to escape a car stalled in floodwaters. One thing reported in the media reiterated by others I know was the generosity of allowing strangers in their homes after being totally blocked off by floodwaters late at night.

Where were you on this day? Tell of your experiences of this event and how it affected you?


Jimmy Deguara
« Last Edit: 03 August 2006, 02:00:21 AM by Jimmy Deguara »
Australian Severe Weather

Australian Thunderbolt Tours

Phone  0408 020468  (International :  61  2  408 020468)

Jeff Brislane

  • Guest
Re: 5th August 1986 Floods - where were you?
« Reply #1 on: 02 August 2006, 02:41:04 PM »

An awesome event and one I also remember with great fondness. On the 5th of August I convinced my mum to let me stay home from school and go to work with her instead at seven hills ( it was also her birthday). I was riding my bike to school at that stage and I convinced her that I would get too wet! Anyway the train trip was one i'll never forget. As we crossed sth creek between werrington and st marys I was absolutely blown away to see the entire floodplain under a torrent of turbid brown water!

The water was in fact as high as about 1 foot or so underneath the tracks of the railway bridge that spans the 1 kilometer wide flood plain. Something I have never seen since nor probably will. The water height was at least 15 meters above normal level! I also recal seeing tv frootage of the massive lake created by the flooding from riverstone al the way to windsor. Apparently it took weeks to completely drain and was visible from space.

I also remember the constant torrential rain that day. I have seen rain as heavy since but not for as long.
« Last Edit: 02 August 2006, 02:43:53 PM by Jeff Brislane »

Offline Geoff Thurtell

  • Multi-vortex F1
  • *
  • Posts: 49
  • Gender: Male
Re: 5th August 1986 Floods - where were you?
« Reply #2 on: 06 August 2006, 10:50:42 AM »
I remember the continuous torrential rainfall on that day. The guttering on the roof at work could not cope and there was water gushing everywhere. I was working at Villawood at the time and the flat terrain meant that there were sheets of water everywhere. I was living at Dundas then. I left Villawood at 4pm and did not reach home until 9pm. Getting through Granville was the most difficult part of the drive. All of the creeks broke their banks and every road had flooding to some extent. I was driving a 4WD at the time, so I was able to get through where others were turning around. Bold Street and Pararmatta Road at Granville were so deep in water that no wheeled vehicles could get through. Some boats were launched! It was a very circuitious route home that night. Some of my colleagues from work lived at Fairfield. They simply could not reach their homes and they spent the night at Fairfield Hospital.
I also had a caravan in a caravan park on the Hawkesbury River. Luckily, some of my friends got there before the flood peaked and they moved my caravan to higher ground. It wasn't the highest flood that I observed on the Hawkesbury, the 1990-1991 flood events were higher than the 1986 event.
That is the significance of the 1986 flood as the heaviest rainfall was in the metropolitan area. The catchment area did not receive the high rainfall of the coast and as it had been dry, the dams caught all of the water. The flooding on the Hawkesbury was mainly from the South Creek/Eastern Creek catchments.
The 1990-91 floods had a lot of rainfall in the catchment areas and the dams were spilling, adding to the flood levels on the Hawkesbury. Ah, those were the days... we had too much water back then!  :)