SIGNIFICANT WEATHER - DECEMBER 1997

Introduction Bushfires Cyclones Thunderstorms Wind Temperature Rainfall

INTRODUCTION

There was no shortage of significant weather this month. Most notably, the fire season picked up speed and severity, especially in Victoria and New South Wales, fulfilling expectations stemming from the current El Nino event, and causing the loss of seven lives in NSW and WA. Six out of seven Regions also recorded severe thunderstorms, and tropical cyclone Sid caused wind damage, heavy rain and flooding in the Northern Territory. Another tropical cyclone - Selwyn - remained well west of the WA coast.

BUSHFIRES

New South Wales

A serious fire outbreak affected NSW during late November 1997 through to early January 1998. There were over 250 fires across the State which burnt a total area in excess of 500,000 hectares. Four firefighters died whilst fighting the fires. The largest individual fires were the Pilliga (150,000 Ha), Muswellbrook/Singleton (105,000 Ha) Wollondilly (80,000 Ha), Hawkesbury (55,000 Ha), Shoalhaven (40,000 Ha), Lithgow (26,000 Ha) and Merriwa (25,000 Ha). Sydney itself was threatened on 2nd December with fires burning in southern and northern bushland suburbs.
The Bureau of Meteorology provided over 700 site specific fire forecasts during this time and issued warnings of very high to extreme fire danger for various parts of the State on 11 days during December. Very high to extreme fire danger was most widespread on the 2nd, 17th, 18th and 21st of December.

Victoria

On the 31st a bushfire started in the Snowy Ranges north of Heyfield. The Department of Natural Resources and Environment requested a fire weather outposted service, and a forecaster was sent to the control office at Heyfield. The fire spread rapidly due to a hot, strong and dry unstable northwesterly airstream.

Tasmania

Fire fanned by strong winds on the 21st caused $300,000 damage to the University Farm at Cambridge.

Western Australia

Early in December approximately 250,000 hectares of country were burnt in the Karijini National Park. The park is located in the Pilbara to the south of Wittenoom.
A devastating fire razed the Brookton - Pingelly area (southeast of Perth) on the 15th. Two people died, and approximately 27,000 hectares of land and an estimated 20,000 sheep were burnt. On the same day there were numerous other smaller fires in the vicinity of Perth at Bindoon, Gnangara, Hope Valley and Kalamunda, and to the northeast of Albany at Gwonellen. A volunteer firefighter died as a result of severe burns from the Gwonellen fire.
Between Christmas and New Year an estimated 50,000 hectares of country was burnt in the Fitzgerald River National Park to the west of Esperance near the south coast.

CYCLONES

Northern Territory/Queensland

Tropical cyclone Sid formed near Croker Island, about 250 km northeast of Darwin on the 26th of December. The cyclone moved eastwards along the coast and passed close to Nhulunbuy, then into the Gulf of Carpentaria where it intensified to a weak category 2 cyclone. Trees and power lines were felled in Nhulunbuy and at Alyangula on Groote Eyland in winds gusting to 85 km/hr. A catamaran was wrecked and several other boats dragged their moorings at Gove Yacht Club during the cyclone. Heavy rainfall and flooding was reported in coastal areas around the Top End and the Gulf of Carpentaria.
TC Sid entered Brisbane (Tropical Cyclone Warning Centre) area of responsibility in the Gulf of Carpentaria on the 28th . The warning was cancelled at 11:00pm on the 28th when the system was located 50 km west of Mornington Island and still over water. No damage was reported although the remnants of the cyclone may have caused local flooding after crossing the coast.

Western Australia

Tropical Cyclone Selwyn formed about 650 km east southeast of Christmas Island on the 26th Initially the system developed slowly and moved along a southwesterly path. However, by the 28th the system was upgraded to severe Tropical Cyclone Selwyn with an estimated central pressure of 960 Hpa. During the following days, TC Selwyn adopted a general west-southwesterly path and commenced to dissipate as a result of vertical wind shear. The last warning was issued on the 2nd of January 1998 when the decaying storm was located approximately 800 km southwest of the Cocos(Keeling) Islands.

THUNDERSTORMS

Queensland

A severe thunderstorm at Gladstone on the afternoon of the 15th produced about 60 mm of rain in one hour.
Severe thunderstorms in the Mary Valley on the afternoon of the 20th brought down trees and power lines, the worst hit areas were in the Kandanga and Imbil districts.
Severe thunderstorms in the Brisbane area on the 27th caused no serious wind damage but produced rainfall rates in excess of one in ten year return period in some areas.

New South Wales

On the 5th, large trees were blown down by 148km/hr wind gusts 50km north of Manilla (North West Slopes).
On the 7th, Murrurundi (Hunter) received 62mm of rain in 135 minutes and Casino (Northern Rivers) 44.4mm in 58 minutes.
On the 18th, 94km/hr gust caused roof damage at Dubbo (Central West Slopes).
On the 19th, 93km/hr wind gusts, hail up to 5cm and 40mm of rainfall in 40 minutes was reported from a number of northwestern and northeastern Sydney suburbs causing damage to roofs, trees, cars and other property. At Tamworth (North West Slopes), winds gusted to 89km/hr and hail which was jagged, layered and measured at 12.7cm caused tree damage. Wee Waa (North West Plains) had 2cm hail with many trees blown down. At Gloucester (Mid-North Coast) 102km/hr winds blew down trees and caused structural damage to sheds.
On the 21st, Dubbo received 2cm hail and 50mm of rain in 30 minutes. At Coonamble (Central West Plains), 94km/hr wind gusts brought down trees and bent aerials. At Williamtown (Hunter), 98km/hr gusts resulted in the drowning of one person who was tipped off a boat on Lake Macquarie. Damage was also reported from Lake Macquarie City, Newcastle, Port Stephens, Corranbong, Cessnock, Muswellbrook and Singleton.
On the 22nd, Coutts Crossing (Northern Rivers) received 2.7cm hail, 50mm of rain in 20 minutes and 93km/hr wind gusts which snapped gum trees. Port Macquarie (Mid-North Coast) had 2cm hail. On the 26th, Wyoming and Rutherford (Hunter) had 2.5cm and 2cm hail respectively.
On the 27th, Werris Creek and Tambar Springs (North West Slopes) experienced wind gusts to 89km/hr which resulted in damage to power lines, trees, roofs and cars. Similar winds and damage also occurred at Mungindi and Gurley (North West Plains).
On the 30th, Moree (North West Plains) received 3cm hail.

Victoria

On the 12th, a severe thunderstorm was reported at Marysville and Buxton, in the North Central district. 32.6 mm of rain was recorded in 20 minutes, and the Maroondah Highway was blocked due to fallen trees.
Severe thunderstorms occurred in the Northeast, Gippsland and North Central districts on the 13th. Winds with speeds estimated at around 100km/hr caused damage to trees and buildings near Wangaratta, Boorhaman, Benalla, Myrtleford, Corryong, Ferndale, Fernbank and Orbost. There was an unconfirmed tornado sighting near Alexandra. 35 mm of rain fell in 30 minutes at Orbost. Lightning struck a house at Sale, causing damage to switches and fuses.
Sparse hail, 2 cm in diameter, and strong wind gusts were reported with a storm at Eskdale in the Northeast on the 14th of December.

South Australia

On the 7th, heavy rain with thunderstorms caused local flooding at Nullarbor and Ceduna on the West Coast. At Nullarbor 29 mm fell in an hour and at Ceduna 49 mm fell in a couple of hours.
On the 8th, severe thunderstorms occurred in the Northwest Pastoral and Flinders districts. At Woomera the wind gusted to 96 km/hr. In the Hawker area, a house and shed were unroofed, gum trees uprooted or snapped off half way up and a tank thrown more than a hundred metres over a building. In Hawker 25 to 33 mm was recorded in 10 minutes.
In the early morning of the 13th wind gusts with a thunderstorm blew down trees and a shed in Port Pirie. In the afternoon, a severe thunderstorm produced a 20 km long swath of wind and hail damage on Mt Sarah Station north of Oodnadatta. A shed was demolished, airconditioners on the house damaged, a 5,000 gallon tank blown away, many redgums lost branches and much of the vegetation was stripped of foliage. 47 mm of rain was recorded.
On the 17th severe winds with thunderstorms blew down trees at Marla, unroofed a house at Fregon and destroyed a shed at Amata (all in the Northwest Pastoral district).

Western Australia

On the 3rd isolated hail to 2.5 cm diameter was observed in parts of Albany township at around 5 am. Later that morning the Albany airport reported some pea-sized hail around 8.30am. There were no reports of damage.
On the 4th the automatic weather station at Forrest registered wind gusts to 90 km/hr as storms moved over southeast parts of the state.
On the 7th storms associated with a mid level disturbance produced heavy rains in the southeast of the state. Localised flooding developed in an area about 300km to the east of Kalgoorlie as notable rainfall totals were registered at Seemore Downs (140 mm), Kinclaven Station (137 mm) and Kanandah (95 mm) in the 24 hours to 9am on the 8th.
On the 10th localised flash flooding and hail to 2 cm diameter occurred at Manavi, 15 km to the east northeast of Watheroo in the Northern Agricultural district. 67 mm of rain fell in one hour.

Northern Territory

A squall line embedded in the circulation around Tropical Cyclone Sid produced damaging gusts in some Darwin suburbs during the evening on the 26th. A thunderstorm down burst produced a gust of 93 km/hr at Woolner Station, 35 km east of Darwin on the same day. No damage was reported.

WIND

Tasmania

Strong winds in Bass Straight on the 17th delayed the crossing of the Devil Cat ferry to Melbourne.

TEMPERATURE

Highest Daily Maximum Temperature for December

                                        Previous             Years of
Station            Actual     Date      Highest      Year     Record
                     øC                  øC               

Queensland

Lady Elliot Is      32.3       22        32.1        1986       41

Western Australia

Albany AMO          42.8       23        41.0        1983       33
Geraldton           46.8       26        46.7        1968       56
Meekatharra         45.3       31        45.0        1972       48

Highest Daily Minimum Temperature for December

     
                                        Previous             Years of
Station            Actual     Date      Highest      Year     Record
                     øC                  øC    

Queensland

Surat               28.8        7        27.2        1976       35

Western Australia
                              
Meekatharra         31.7       30        30.8        1972       48

Highest Mean Minimum Temperature for December

     
                                   Previous                  Years of
Station            Actual          Highest          Year     Record
                     øC              øC      
                
Queensland

Richmond            24.8             24.3           1987        90
Collinsville        23.2             23.0           1981        43
Taroom              22.5             21.2           1957        46
Longreach AMO       24.1             23.9           1987        32
Springsure          22.2             22.0           1979        51
Winton              25.0             24.9           1990        60
Birdsville          25.9             24.4           1988        44
Baralaba            22.2             22.0           1979        31
Gayndah             21.7             21.5           1979        94
Maryborough         22.2             21.9           1911        90
Injune              20.4             19.9           1979        31
Quilpie             25.3             24.5           1982        57
Thargomindah        24.7             24.6           1990        60

New South Wales

Grafton             20.6             20.2           1990        32
Lismore             19.6             19.5           1946       114
Port Macquarie      19.7             19.3           1990       158
Lithgow             13.0             12.9           1988       109
Nowra RAN           15.9            =15.9           1973        56

Highest Mean Maximum Temperature for December

     
                                   Previous                  Years of
Station            Actual          Highest          Year     Record
                     øC              øC

New South Wales

South West Rocks    28.1            =28.1           1990         59
Taree               31.6             31.5           1990        117

Australian Capital Territory

Canberra A/P        21.5             21.1           1940         59

RAINFALL

Highest Annual Rainfall on Record

     
                                   Previous                  Years of
Station            Actual          Highest          Year     Record
                     mm              mm

Queensland

Mount Isa AMO       919.0            864.6          1974         29
Devoncourt Stn     1157.9           1013.9          1950         85
Duchess            1092.4            921.1          1984         75

Western Australia

Broome             1454.0           1227.6          1974         57
Mininer             679.2            473.6          1984         32 
Mount Vernon        700.8            467.5          1942         56
Wittenoom           839.9            825.0          1995         46

Highest Daily Rainfall on Record for December

     
                                        Previous             Years of
Station            Actual     Date      Highest      Year     Record
                     mm                    mm

Queensland

Burketown -
  Westmoreland      229.0      29        163.1       1969        33
Mareeba QWRC        125.0      29         70.4       1973        46
Ravenshoe -
  Koombooloomba     138.0      30        127.0       1973        38
Wuruma Dam           92.0      24         75.0       1988        33
Applethorpe          71.0      24         61.2       1989        30
Talwood-Cheriton     87.6      09         71.9       1965        64
Thallon PO          123.4      08        114.0       1980        86
Thallon -
  Moonie River      114.0      09        111.0       1980        45

Highest Monthly Rainfall on Record for December

     
                                   Previous                  Years of
Station            Actual          Highest          Year     Record
                     mm               mm

Queensland

Burketown -    
   Nardoo           234.3            231.0          1983         34
Burketown -
   Westmoreland     505.4            405.0          1975         33
Mount Isa AMO       171.2            165.2          1977         32
Chillagoe           418.0            416.9          1944         96
Dimbulah            322.4            233.1          1942         67
Mt Garnet PO        326.6            312.5          1903         97
Mt Garnet -
   Meadowbank       445.0            258.9          1965         42
Thallon             219.8            180.6          1942         86

New South Wales

Bellata PO          234.6            205.0          1970         86

Northern Territory

Ammaroo             124.6            101.8          1975         40
Minjilang           624.6            623.1          1949         45
Mittiebah           272.4            159.6          1996         27

Lowest Monthly Rainfall on Record for December

     
                                   Previous                  Years of
Station            Actual          Lowest           Year     Record
                     mm               mm                    

Victoria
          
Kyabram               0.0              0.4          1995         34
Korumburra           12.6             14.8          1960         93
Oakleigh              6.0              6.7          1972         82