Spectacular Tornadic Squall Line

November 24, 1998

The morning started out generally fine.  Very few clouds, except for some cirrus and some isolated altocumulus castellanus which was a promising sign! However there were no visible signs of convection before 10am from my position.  At 10am, I went and saw a movie with some friends at Noosa Junction.  The movie finished at about 11:30am, and as soon as I walked outside I saw TCU to the SW with a lot of cirrus streaming out from behind it!  I immediately had to part with my friends for 20 minutes, as I raced to a net café to look at lightning tracker and any warnings (if they were out)  The web lightning tracker is about 15-20 minutes behind the current time, but at 11:20am there were already many lightning strikes around the border areas and near Stanthorpe!  Also, top priority severe thunderstorm advices were placed, which made me very excited!!

By 2pm though, the sky was covered completely by cirrus, but still with a lot of well developed cumuli around.  The pressure was 1003hPa and falling.  Generally the sky kept fairly quiet until about 3:30, then it began to get very dark to the SW and S, I literally saw the barometer drop before my eyes - 1002, 1001, 1000hPa!  By 3:45, I was out beside the highway watching CG's hit the water probably about 40-50km south! By 4:15pm, a shelf cloud appeared on the horizon.

It looked very deep, crisp and certainly well defined.  However what initially appeared as a good shelf cloud, soon became an awesome shelf cloud!  It was very well rounded, very low, deep and certainly very ominous!  In fact, I counted 4 cars that actually turned around in the opposite direction!  I could continue seeing CG's to me SE, I also saw 2 other shelf clouds in the distance to the south, and of course my shelf cloud to the SW.

I was expecting something very severe, the sky was a dark emerald green and I had never seen such a shelf cloud before in my life!  What I got was certainly a surprise.  As the gust front came over, I received winds of about 50km/h for between 20 and 30 seconds.  After this there was some light rain, and a light to moderate southerly blowing.  There was some good lightning and thunder, including a lovely CG about 200 metres away over the water!  However I received only about 3-4mm of rain, and I was extremely surprised.  I was expecting something huge!  But I didn't get anything, yet just 5km south of me at Perigian Beach there was some rather bad roof damage.  Probably the most interesting event out of all, were the two gustnadoes/waterspouts that developed on the gust front as it passed over the water.  There were two, rotating structures about 5-10 metres high and 50 metres apart.  It appeared to be analogous to a dust-devil but for obvious reasons it wasn't one!  They only lasted for about 2 minutes, before disappearing, unfortunately due to the nature of my camera, they did not come out very well when I attempted to take apicture of them.

For the next hour, there was light thundery rain.  To say that I was disappointed would be a massive understatement!  The total extent of the damage was quite widespread.  Over 107,000 premises lost power at the height of the storms, this broke the record for the most number of premises without power in SE QLD.  There was also a scattering of minor structural damage in Brisbane, and one area where a microburst knocked down an area of trees along a road.  Energex reported that they actually had to rebuild the network in areas such as Brookfield because of the huge damage of the network!  Trees, large branches and lightning strikes were the cause of this.  The most interesting report was the tornado in Caloundra.  According to the Bureau of Meteorology, the tornado was given an F1 rating. It damaged eight homes, partially unroofing them.  It also partially destroyed an old weatherboard and brick duplex home.  There were numerous reports of funnel sightings within the area.  While visiting the BoM, I was also sent some pictures of the tree damage of what is thought to be tornado track.  It is presumably the same tornado, but rather the funnel 'skipped' along.

After what appeared to be a very quiet season, with below average temperatures and DP's, and with another 'death ridge from hell.'  Thethunderstorm season for SE QLD has picked up remarkably!