The October and November 2007 rain events Page 1

22nd October 2007 low, storms and rains

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Its hay season in the hills. So it goes without saying that it will rain in the most inconvenient way possible. Murpheys law in operation!!! It starts with heat on the 21st. A stinker of a day with strong hot northerlies and temperatures in the hills near 30 degrees and mid thirties in the city. Meanwhile out west along the approaching trough line the heavens were firing up an electrical storm as can be seen from the 24 hour map to the right! But it was mostly stationary along this line and not going to make it to the central districts overnight. A few showers finally made the central districts in the early hours of the morning from an amazingly long and linear rain band that almost traversed the whole state! See image to the far right. Nothing more than 1.5mm from this.

 

Morning on the 22nd dawned grey and heavily overcast with a solid deck of altostratus. Overnight a nice little low had strengthened int he bight and looked fantastic on the satellite. See the image to the right. The sky was unstable and by mid morning a line of showers and heavy rain cells was developing from the mid level deck of cloud. Remember what I said about hay on the ground? Rain when you need it the least! And rain it did. Solid big drops and consistent. By 4:30pm in the afternoon 10mm was in my gauge. This is the highest 24 hour fall in over 6 weeks and it fell in just a few hours! Some irony indeed. The rain kept on coming and by morning of the 23rd I had an amazingf 25.5mm in the gauge. This topped the local rainlist. Again quite an irony considering I had just cut hay. It is a significant 24 hour total in that it was the 4th highest 24 hour total for the year to date. Thats crazy stuff considering its late in October. Do I need to mention the irony again? The 23rd dawned foggy. Not just any fog, but a pea souper.

This fog persisted until midday, streaming in from the east. When the fog finally lifted it left behind a solid stratus deck that locked out any warmth, compounded by a cold easterly wind. As such conditions were cold all day with temperatures hovering around the 10 degree mark. This is extremely unusual and I have yet to record such cold daytime conditions this late in October.

Meanwhile in the Mid North something else entirely was going on as big storms exploded. The BOM issued a warning

SEVERE THUNDERSTORM WARNING for FLASH FLOODING, DAMAGING WIND and LARGE HAILSTONES For people in the Eastern Eyre Peninsula, Flinders, Mid North and parts of the Yorke Peninsula and Northeast Pastoral districts. Issued at 4:19 pm Tuesday, 23 October 2007. Severe thunderstorms are likely to produce very heavy rainfall and flash flooding in the warning area over the next several hours. Some of these severe thunderstorms may also produce damaging winds and large hailstones in the Flinders and Northeast Pastoral districts. Locations which may be affected include Whyalla, Port Augusta, Port Pirie, Clare and Jamestown. Several reports of very heavy rainfall in excess of 50 mm have been made, which has resulted in local flash flooding. Places affected include Kadina, Moonta, Crystal Brook, and Laura.

Radar Loop of the Yorke Peninsula storms

The radar loop above shows one of the most amazing displays of storm activity you will see. The Kadina cell is being "pulled into" the Bute cell while the Lochiel cell is moving in towards the same cluster. Intensity is at maximum and likely hail! Reports started rolling in as storms further north hammered local district centes.

 

School group affected by lightning Tuesday October 23, 2007 - 16:40 EST A teacher and his students have been affected by lightning during a thunderstorm in South Australia, when the lightning struck a school sports oval they were on. The sudden storm struck at Port Broughton, south of Port Pirie, as a wave of thunderstorms moved across northern areas of SA. The teacher, 33, and some of his students have been taken to Port Broughton hospital. Megan Cree from the ambulance service says they have various symptoms. "Students are currently being assessed with symptoms including headaches and tingling sensations," she said. Medical staff report that the teacher is in a satisfactory condition but will be kept in hospital overnight, as will three or four students. The storms have caused flash flooding across a wide area of SA. The State Emergency Service (SES) says part of National Highway One in the mid-north of SA has been flooded. At Crystal Brook, about 50 millimetres of rain fell in half an hour. The usually dry creek there burst its banks and the town's caravan park had to be evacuated. At Moonta on Yorke Peninsula, publican Catherine Duncan reported significant damage. "We had water coming through the light fixtures all the way down the walls," she said. Another resident Kayla Yandell was mopping up at premises in the main street of Moonta. "We have a box gutter down the middle of our house and it just let go and all our electrical goods are damaged," she said. Residents of Booleroo Centre, further east, reported severe hail storms. SA storms cause flash flooding Tuesday October 23, 2007 - 15:22 EST The State Emergency Service (SES) says part of National Highway One in the mid-north of South Australia has been flooded by a thunderstorm. The SES says residents at Crystal Brook have reported 50 millimetres of rain in half an hour. Trevor Arnold from the SES says there have been dozens of callouts to deal with flooding. He has warned drivers to slow down and keep out of water on the road if they can. "It's probably over 20 kilometres or 30 kilometres I would suggest," he said. The usually dry Crystal Brook creek has burst its banks, leading to an evacuation of the town's caravan park. Police say drains have become blocked as water covers two major roads. There have also been reports of heavy rain at Moonta on Yorke Peninsula. Catherine Duncan from the Moonta hotel says there has been some significant damage. "We had water coming through the light fixtures all the way down the walls," she said. The rain has been widespread across northern parts of SA. - ABC © ABC 2007

AWESOME STUFF!! Rainfall amounts approaching 100mm are possible from some locations!

The satellite image and associated lightning strike archive image are pretty impressive too. The overshooting cloud tops are clearly visible.

Above - lightning archive Left - associated sat image

Sundown saw the action die off a bit, but further north the storms continued with a huge area between canopus, Gluepot and Hallet under a massive rotating combined storm complex that looked to have formed its own "thunderstorm low". Late evening and it was going again over northern Yorke Peninsula. Rain only this time, but the lines of development are amazing.

Radar image from10pm on the night of the 23rd showing the significant storm and rain developmet over the mid north.

RAINFALL TOTAL UPDATE

The rainfall totals for the mid north thunderstorm event are in and somehwat impressive to say the least! I will just list a few of the top recordings here. A full statewide rainlist is available on request. Recordings are in MM.

• Braemar 96
• Georgetown 75
• Laura 64
• Paratoo 59
• Crystal Brook 46
• Carrieton 43
• Whyte - Yarcowie 40
• Mt Bryan 36
• Moonta 34

You have to wonder just what some of these totals would have been like in the locations that are not part of the rainfall network. Some falls well in excess of 100mm in isolated spots must have been possible!

Pics from the mid north

A few pics taken by people in the thick of the action can be seen in this small gallery as well. I was stuck at work but its great to have these images contributed.

Move on to the next page and more rain!