Michael Thompson's Australian Storm Chase Diary

16th November 1997 ' Clarence River Valley $3 Million storm '
Updated 8th February 1998 with eye witness report from Junction Hill

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With a weeks holiday spare I decided on a combined fishing / storm chasing trip to the seaside town of Yamba on the north coast of New South Wales. Yamba would be a better situated base for potentially severe storms then my home town.

The trip takes 11 hours of driving. We left on Saturday 15th of November at 4am. Thunderstorms were forecast in a trough stretching across southern Queensland and into New South Wales. A weak cold front had passed my home at 10pm the previous evening. I knew that this front would stall somewhere north of the Central Coast. This would enhance storm activity. Next morning during the trip north, signs of any front were completely gone by the mid north coast town of Taree at 10.30am. There was however some patchy rain in the trough area, to the west clearing had occurred and already cumulus was forming in the clear areas. However, the trip to Yamba took us through to the other side of the trough which appeared not to be favouring storm development. That evening a severe storm advice had gone up for the mid north coast. At 9pm I drove to a tall headland and could see lightning a long way to the south.

Next morning was clear , very warm and humid. The trough had moved over the north coast overnight, and the middle level cloud had cleared. I filled in the morning fishing. To the west I watched as several cumulus clouds grew over the Great Dividing Range. By midday one of these had matured into a storm. The most distinctive feature that caught my interest was the amount of pileus cloud. At first just topping the tower, but later obscuring almost all the cell except for the forward anvil

I kept an eye on the storm over the next 2 hours whilst I took a refreshing swim at the beach. The storm had moved almost to the coast by now. When it was close enough to hear distant rumbles of thunder I decided it was time to think of a possible chase. I raced to the cabin and grabbed my camera. In the short few minutes that it took to get the camera gear several CG's on the rain free north side of the storm had taken my attention. I decided that the best option was not to chase as such, but stick right where I was.

This proved to be a fortunate move. Whilst initially it was a round a CG's that grabbed my attention, I now focused on a downdraft area to south west, the speed at which it was moving and its general features indicated that possible downburst activity was happening. I managed to get several good shots of this powerful downdraft. I later learnt that this event caused widespread damage to sugar cane crops at Palmers Island, completely flattening large areas. There was some reports of minor structural damage and trees uprooted.

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My view to the south was obscured by large Norfolk Island pine trees, therefore I was taken by surprise when the odd large hailstone started falling. I was expecting hail, ( see the portrait photo ), but still thought I had about 10 minutes. I beat a hasty retreat back to the cabin. Hail was a mixture of sizes from pea to around golfball. Hail fell for about 2-3 minutes before any rain. The wind rose to about 40 knots. The storm lasted about 15 mins, before passing out to sea. I was very surprised to see that the rear end of the storm ( see pileus photo above ) was quite tame looking. I doubt that the storm was a supercell. It appeared to be multi-cell for a start, I saw no rotation either.

Reports started filtering in about the serious damage that this storm caused earlier at Grafton. Local media reports indicate damage running to $3 million. This was not counting any rural crop losses, only town damage. The Grafton suburb of Junction Hill bore the brunt of the storm. This occurred at approx 1pm, a full two hours before the photos above. As well as numerous roofs, some houses received major structural damage. Local estimates indicated winds to 160kph.

The trip around the district later in the day showed that Yamba had been spared the worst. At Palmers Island there were large areas of sugar cane crop flattened. Where there were trees, leaf and twig litter was almost completely covering most of the road. A few small trees had been uprooted. I drove several kilometres southwards on Palmers Island and all damage was straight line. Cane was laying east - north east, indicating west to south west wind direction. Most of the photos above were taken at Yamba looking up the Clarence River towards Palmers Island.

Driving home a week later and I noticed that the small town of Ulmarra had also seen severe winds. To the east of town many casuarina trees lining the Clarence River had been uprooted.

EYE WITNESS REPORT by Ian Wright
The storm lasted only 16 minutes at Junction Hill, my Davis Instruments
weather monitor, redgistered wind speed at 206 km before it was taken out
of service by flying rubbish,  the temperature droped from 36.6c   to
19.4c in 12 minutes prior to the storm,  the Brisbane weather beau. radar
said the storm was picked up at 21km high just prior to the "down burst",
only marble sized hail was seen here but the amount was stagering. in one
place there was 2qubic metres of hail in a 5 Square meter area,  I have a
great photo that I'm sending to Michael Bath taken form the side of the
storm at about 1 1/2km from it"s centre just seconds after the Down Burst
hit the ground I may be able to get you a copy if you can give me an
address to post to.
I have been a weather watcher for a long time now and have never seen
anything like this event.  I spent 25 years in the State Emergency Service
10 yrs. as controller of a unit and have never witnessed anything so severe
before,  if I can be of any further help please contact me on this email
add.
ian@key.net.au