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SIGNIFICANT WEATHER - OCTOBER 1999
Severe thunderstorms accompanied by hail and damaging winds occurred in several States during October. Bushfires affected areas of northern Western Australian and parts of the Northern Territory. Queensland On the 4th severe thunderstorms brought widespread torrential rain to the southeast with flash flooding in Ipswich, Brisbane's western suburbs and the Gold Coast. Hail was reported and powerlines were downed in Ipswich. More than 5000 homes lost power. On the 14th small hail, strong winds and heavy rain caused local flooding near Nanango (Moreton). During the late evening of the 20th and early on the 21st a small intense storm passed down eastern Brisbane suburbs with light hail, intense rainfall and strong wind gusts. A demountable building was tipped over at Brisbane airport and a rainfall rate of 200mm/hr was recorded at the airport in a 20 minute period. On the 23rd severe thunderstorms with extensive hail (some larger than golf balls) destroyed crops in fruit growing areas from Texas to Stanthorpe. Damage estimates range from $10M to $30M. Strong winds also caused structural damage to a house and felled powerlines. On the 24th large and small hail was reported in the Ipswich and Sunshine Coast areas with 3500 homes losing power. On the 27th a severe storm caused flash flooding in Bundaberg with 158.4mm being recorded in a 2 hour period. New South Wales On the 1st at Granville (Metropolitan) 34.5mm of rain fell in 30 minutes which resulted in flash flooding. Seven Hills and Kingswood received 31mm in 25 minutes. Roads were blocked by water at Toongabbie. On the 9th at Broken Hill (Lower Western) a wind gust of 93 km/h was experienced. On the 10th in the Riverina 2cm diameter hail was reported at Finley and at Jerilderie 32mm of rain fell in 30 minutes and gusts to 150 km/h were experienced. This resulted in damage to the fire station roof. On the 14th at Valetta (North West Slopes) 75 km southwest of Moree, 3.5cm diameter hail was reported . Wheat crops were wiped out and trees stripped. At Wee Waa (North West Plains) 3cm hail was reported between Wee Waa and Narrabri which destroyed cotton crops. At Mullaley (North West Slopes) 4.2cm hail was reported and 76.2mm of rain fell in 40 minutes. There was extensive damage to crops, trees, sheds and some roof damage. Hail blocked downpipes and caused internal damage to a home. Some flooding was reported. On the 18th at Canobolas (Central Tablelands) 2.5cm diameter hail was reported. At Raymond Terrace and Toronto (Hunter) 26mm of rain fell in 20 minutes and flash flooding occurred at Toronto and gusts to 104 km/h were reported at Raymond Terrace. On the 23rd at Mendooran (Central West Slopes) 3cm diameter hail was reported. Trees were defoliated, crops flattened and a raingauge was smashed. On the 24th at Taree (Mid-North Coast) 6cm diameter hail and some property damage was reported in the area. At Kendall (Mid-North Coast) 5.5cm diameter hail was reported. Windows and skylights were broken and cars dented, gardens were stripped and tanks were holed. At Palmers Island (Northern Rivers) 4.4cm hail was reported and 36mm of rain fell in 15 minutes with gusts to 148 km/h. Hail 2cm in diameter was also reported from Iluka. Two sheds were demolished and crops were destroyed. Other minor damage was also reported. Victoria On the 10th and 11th severe storms occurred in the Mallee, Wimmera, Central, North Central and Northeast districts. Some crops were damaged or destroyed by large hail (up to 4cm in diameter) at Kaniva, Robinvale, Woomelang and Mildura. Heavy rain was reported in the other districts. South Australia A complex low pressure system and associated unstable atmospheric conditions moved across the state on the 2nd. Thunderstorms with hail caused significant damage to wine grape crops in the Clare Valley and Lower North district during the afternoon with an area10 km long and 2 km wide between Auburn and Leasingham being the hardest hit. Hail stones the size of golf balls stripped grape vines and damaged property within this area. Further north, between Robertstown and Jamestown, heavy rain caused flash flooding. A similar event with no official gauging was reported near Point Pass. A second complex low pressure system was positioned southwest of Kangaroo Island on the 9th. A moist trough was associated with this system. Ahead of this trough conditions were warm and humid. Thunderstorms developed in the warm humid air along the moist front, during the early afternoon, in the Upper Southeast district. A thunderstorm caused significant damage to cereal crops, fruit trees and property west of Bordertown and 40.6mm of rain was recorded at Bordertown for the weekend. Northern Territory On the 7th a thunderstorm downburst near Darwin River Dam damaged a shed, water tank and large trees over a localised area. On the 16th 1.5cm diameter hail was reported at Berry Springs and thumbnail sized hail at Southport and Darwin River. Wind gusts associated with the same storm were estimated at 80-90 km/h but no damage was reported. On the 28th small hail was reported during an afternoon thunderstorm at Palmerston. Tasmania Wind gusts exceeding 90 km/h were reported from the Derwent Estuary (near Hobart) on the 9th, 22nd 27th and 31st , Mount Wellington (near Hobart) on the 8th-9th, 15th-16th, 26th-27th, 29th-31st and at Cape Grim BAPS on the 31st. No significant damage was reported. Western Australia On the 7th and 8th strong to gale force, squally winds affected a large area of the southern half of Western Australia as a very active cold front associated with an intense low crossed the west coast. The high winds caused damage about the region as gusts to over 90 km/h were registered in the Lower West and Southwest. On the 7th Rottnest Island reported a gust to 113 km/h and at mainland sites notable gusts were registered at Cape Naturaliste (106 km/h) and Swanbourne (100 km/h). The strong winds also buffeted the south coast where Albany reported gusts to 78 km/h and Esperance had gusts to 83 km/h. Inland, Cunderdin (central agricultural district) registered gusts to 91 km/h. Electricity supplies were interrupted as falling branches brought down power lines. Around Perth several properties sustained severe structural damage to roofs and ancillary buildings. About 19km to the southwest of Wagin (southern agricultural district) a tornado cut a path about 200 metres wide and 4 kilometres long on the 7th. Several sheds, grain silos and numerous trees were damaged during the event. On the 13th and 14th the passage of a series of cold fronts produced strong winds around the southwest land division. Cape Leeuwin registered a gust to 113 km/h and other west coastal areas reported gusts of more than 90 km/h including Rottnest Island (107 km/h) and Swanbourne (98 km/h). Gusts above 75 km/h were registered along the south coast and in agricultural areas at Geraldton and Southern Cross. Northern Territory On the 10th a 102 km/h gust was recorded at Batchelor AWS in a thunderstorm microburst. A fuel shed with empty fuel drums at Batchelor Airfield was blown away in the storm and a light aircraft was lifted off the ground. Victoria There was frost around Horsham in the Wimmera district on the 22nd and 23rd which caused about 5 percent loss to grain crops. Frost damage was patchy, the worst area affected was just north of Horsham, although areas to the west and as far as Rapanyup were impacted on. Queensland Duststorms were experienced at Birdsville on the 9th and at Boulia and Bedourie on the 12th. Western Australia Significant areas of the northern half of Western Australia were affected by bushfires during September and October 1999. Northern Territory Dry and gusty easterly winds resulted in periods of near extreme fire danger over the Gulf Country and Barkly region on the 6th, 11th, 24th and 28th. Fresh and gusty northwest winds also produced near extreme fire danger in the western Alice Springs region on the 7th, 8th, 14th and 25th. Lightning caused around 10 fires in pastoral areas between Katherine and Newcastle Waters during the first week of October. Large areas of grassland were burnt in the northern Barkly, western Gulf Country and southern Katherine regions (around 100 square kilometres on Gilnockie Station and 200-500 square kilometres on 7 other stations). Significant loss of pasture and fencing was reported from the affected pastoral properties. Queensland The passage of an upper trough triggered rain and many thunderstorms causing minor to moderate flooding in the Dumaresq and Macintyre rivers between the 29th and 31st.
Note: Some statistical records mentioned in this report are based on data that have yet to be fully validated.
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