|Radar and lightning tracker animation every
two hours from 8.50am yesterday to 12.50pm today, with a final frame at
today. Weatherzone, BoM, Kattron.
QLD: Major flooding claims 3 lives, causes $25m+ damage
Up to 400mm of rain in six hours brought major flash flooding to
the QLD Gold Coast today, while record falls in the Tweed, Brunswick and Richmond
Valleys caused widespread main river flooding. Three
were drowned, while damage estimates are put at over $25m
for home, motor vehicle and general claims, and a further $2.7m in
to community infrastructure. Heavy rain and strong
winds over a broader area of NSW and SE QLD caused widespread lighter damage
and disruption, but delighted drought-suffering farmers, with many grain growers
expecting their best winter crops in five years.
In SE QLD, the torrential rain closed Coolangatta Airport, triggered landslides,
power blackouts and car crashes, interrupted the mobile phone network, inundated
homes and stranded motorists. In NE NSW, hundreds of people were evacuated
as flooding worsened. Ironically, this is one
of the few parts of the state not in
drought. From the Gold Coast to the Illawarra, strong winds brought down trees
and caused roof and structural damage to houses, resulting in nearly 1,500
callouts for SES assistance. NE NSW was declared a natural disaster area,
meaning that people living in the local government areas for Lismore, Byron,
Tweed, Ballina, Richmond
eligible for disaster assistance measures.
analysis at 10am today for 850hPa (about 1.4km above sea level) locates
a band of strong
across NE NSW responsible
for flood rainfall over the previous 24 hours. Weatherzone, BoM
Why it occurred
The surface chart at the top of this page gives little indication of the forces
that generated the torrential rain, variously described as a 1 in 10 to 1 in
30-year flood event. The 10am surface chart shows a broad trough covering much
of QLD and NSW with a specifically marked tighter trough right on the coast
from Fraser Island to the NSW North Coast.
The main cause was the arrival over SA last Saturday of a
trough or meander in the normally westerly upper air flow. During Sunday, the
trough separated from the westerly flow and developed its own circulation,
moving from Adelaide to SW QLD by Monday. In addition to transporting
cold Southern Ocean air in the upper atmosphere across NSW and southern QLD,
the upper circulation began dragging very moist air from the Coral Sea southwards
over QLD and northern NSW.
Between Monday and Wednesday evening, this circulation (or upper low or
cold pool) stalled over the NW NSW/SW QLD border area, but continued to draw
increasingly moist, warm air down its eastern flank in the bottom few kilometres
of the atmosphere. The combination of cold air aloft and the rotation in the
system ensured widespread
uplift in the moist northerlies with widespread heavy rain the result.
late yesterday afternoon to late this morning, a zone of strong convergence
developed in the lower atmosphere, clearly visible in the 850hPa chart for
The strong northeasterlies east of 150°E converging
into the northerlies west of 150°E have
nowhere to go but up, enhancing the uplift in an area of deeply saturated
air and concentrating heavy to torrential rain east of 150°E from
the Gold Coast to the northern Hunter Valley.
|Rainfall for the 24 hours to 9am for NSW above , and below
for SE QLD ,
NE NSW and
the NSW Mid North Coast . BoM
The map of NSW at left ()
shows that totals above 100mm for the 24 hours to 9am were general from the
Gold Coast to the northern Hunter Valley. Totals
to 100mm were widespread on the NSW North West Slopes and Plains. All totals
of 50mm or more are listed in Wettest below
and details of the heavier short duration falls are in Downpours.
The 24 hours to 9am period coincided with much of the heaviest rain, so that
many new June records were set. Known records are listed in Records below,
the most significant being Tweed Heads which, with 386.0mm, experienced its
wettest day since records began in November 1886. Six stations had their wettest
June day in over a century: Tweed Heads (386.0), Mullumbimby (287.0), Woodburn
(275.6), Yamba (250.4), Dungog (132.0) and Gravesend (69.0).
The heaviest 24-hour recordings were all in a band from around Surfers Paradise
through Coolangatta/Tweed Heads to Mullumbimby. The top official figures were
Tweed Heads 386.0, Coolangatta Airport 369.0, Gold Coast Seaway 350.8, Nerang
and the Air Sea Rescue gauge 5km N of Surfers Paradise with 322.0.
However, the flood warning network, where quality control is not assured, produced
some significantly higher 24-hour totals. These included:
Nerang catchment, Gold Coast:
497 Loder Creek Dam
477 Biggera Creek Dam
411 Loder Creek
406 Boobegan Creek Lock
398 Bonogin Creek
393 Tallebudgera Creek Road
381 Coplicks Bridge
378 Oyster Creek
Tweed catchment, NSW:
Brunswick catchment, NSW:
423 Middle Pocket
340 Mullumbimby Creek
Wilsons catchment, NSW:
All of the Gold Coast falls over 400mm are within 7km of Surfers Paradise;
Carrara is 7km WSW of Surfers Paradise. Duranbah is 14km S of Tweed Heads
and Middle Pocket is halfway between Murwillumbah
and Byron Bay.
The heaviest Gold Coast rain fell between about 3am and late morning with
the highest totals in the Nerang catchment. For example, Carrara recorded 432mm
403mm between 4 and 10am. The heaviest known hourly totals were 145mm at Carrara
at Boobegan Creek Lock, both between 7 and 8am. The heaviest 3- hour totals
were all between 6 and 9am, headed by Carrara 284, Boobegan Creek Lock 221
and Evandale 219mm. Coolangatta Airport registered 441mm between 2am and noon,
its heaviest hour's rain being 97.8mm to 6.30am. Gold Coast Seaway recorded
408mm midnight to noon.
The situation was similar in the NSW Tweed and Brunswick catchments, where
3-hour totals to 9am were headed by Duranbah 237, Middle Pocket 165 and Chincogan
122mm. On the Wilsons River, which passes through Lismore, rain was more evenly
spread through the 24 hours to 9am.
Flooding and weather
The radar animation ()
shows rain streaming south down the trough/convergence line. The southerly
movement and relative narrowness of the rainband confined the very heavy falls
to the coast or lower reaches of coastal river
systems, substantially reducing the flooding that would have occurred had
of this intensity fallen in main river headwaters. As the trough skewed offshore
around midday, rain ceased on the Gold Coast and NSW North Coast, easing
the threat of flooding just when emergency services were bracing for the worst.
Strong northeasterly winds were experienced along the coast in the tight
pressure gradient between the trough and a 1037 high in the central Tasman.
The highest average 24-hour wind speeds recorded in the nation to 9am were
49.9km/h at Newcastle Nobbys, 45.8 at Cape Byron, 44.6 at Cape Moreton and
43.0 at Norah Head. Top wind gusts were 109km/h at Cape Byron, 102 at Montague
Island, 95 at Cape Moreton and 93 at Moss Vale. The winds whipped up heavy
seas, with press reports of one wave reaching 10.65m off the Tweed Coast.
The flood and general weather situation in each catchment was as follows:
Brisbane: SES volunteers were required to deal with many
water-damaged homes in Brisbane, Ipswich and Beaudesert. Most southeastern
baysice suburbs of Brisbane recorded over 100mm in the 24 hours to 9am.
Gold Coast: Although there was widespread, severe
flash flooding reported from almost every suburb, the coastal nature
of the heaviest rain resulted in virtually no main
river flooding. In the Nerang catchment, Tallebudgera Creek at Coplicks
Bridge briefly reached major flood stage late morning. The only other flood
reached were minor flooding in Teviot Brook at Boonah and Slacks Creek
at Loganlea Road in the Logan-Albert catchment. Gold Coast City Council said
the level of flooding and damage was the greatest since the 1974 floods.
A couple died when their ute
was swept off the Birds Road bridge over the Coomera river NW of Nerang.
Coolangatta Airport was closed with waist-deep water outside the terminal,
stranding hundreds of passengers. Sixty-seven people were evacuated from their
were flooded. About 120 residents were evacuated from a nursing home, the Miami
caravan park and parts of Biggera Waters. The major Gold Coast shopping centre,
Pacific Fair, was closed at 10.30am when the centre's
retaining wall collapsed at Tugun and Palm Beach homes had to be sandbagged.
Several properties atop Currumbin Hill were evacuated as they were considered
unsafe because of possible landslides. Seven people were trapped in cars in
different parts of the Gold Coast, and a woman
when trapped by rising water. The Gold Coast's four main theme parks were closed
for the first time due to the weather. Flash flooding closed the Pacific Motorway,
the main link between the Gold Coast and Brisbane, at Tallebudgera and many
arterial roads throughout the Gold Coast were closed by flash flooding. Over
26,000 properties lost power when powerlines were brought down by uprooted
branches, car crashes into power poles and washed out underground cables. SES
volunteers responded to more than 600 calls for help.
Tweed: The situation was similar in the Tweed Valley,
where the only gauge to reach a flood stage was Murwillumbah which was above
from late this morning to early Friday morning. Seventy-five nursing home
residents were evacuated at Banora Point.
Brunswick: Following over 400mm in 24 hours at nearby Middle
Pocket, Lacks Creek at Billinudgel peaked at 4.5 metres at 10am with major flooding.
The main street of Billinudgel was evacuated with water knee-high. The Brunswick
River at Mullumbimby Federation Bridge peaked at around 3.5 metres at 9am
with moderate flooding. At Golden Beach, near Billinudgel, 100 people were
plant to back-flood. Flash flooding at Byron Bay required sandbagging to protect
homes, and a man drowned when apparently
overwhelmed by flash flooding on his bicycle near Ewingsdale west of Byron
Bay. The Pacific Highway was closed 3km north of Ballina.
Wilsons and Richmond: With 300 to 500mm falling across
the northern Wilsons River catchment in the 48 hours to 9am, major flooding
was expected in Lismore, the main city on the river, with moderate
to major flooding in the lower Richmond River from Coraki to Woodburn.
However, the sudden cessation of rain in the catchment around noon resulted
levels upstream of Lismore peaking lower than expected, and a peak at Lismore
of 10.2m around 10pm, the highest level since February 2001. The flood
wave was also slow-moving between Lismore and Coraki, not reaching Woodburn
The last major floods in Lismore prompted the construction of an 11m levee
around central parts of the city at a cost of $19m. It is due to be opened
on 1 August, but received and passed an unexpected test today. The highest
was 13m in the 1950s, and when it was feared this morning that the Wilsons
River may top the levee, evacuation of up to 6,000 people in the city was authorised.
When it was realised early afternoon that the levee would hold (the peak was
70cm below the top), the evacuation plan was abandonned, though at a best estimate
some 600 people were evacuated from parts of Lismore not protected by the levee.
were rescued from cars trapped in floodwater, including two in a stolen vehicle
who were promptly arrested.
Orara and Clarence: Again reflecting the coastal nature
of the rain, the only flooding in the large Clarence catchment was in the
coastal Orara system. An average of 150mm was recorded across the Orara
which peaked at 5.5m at Glenreagh around 3am Friday with minor flooding. Flash
flooding at Yamba required sandbagging to protect homes. The Pacific Highway
was closed by local flooding 10km N of Woolgoolga along with most other main
roads in the area.
Bellinger: Minor flooding occurred at Thora from early this morning into Friday with a
peak of 3.86m at 6pm. The river peaked at Bellingen at 3.7m, below minor.
Most low-level bridges over the upper Bellinger were under water.
Macleay: Low level bridges at Bellbrook, Temagog, Turners
Flat, Wittitrin and Moparrabah were covered.
Hastings: Minor flooding in the lower reaches around Kindee
Bridge only. Kindee Bridge peaked at 4.5m around noon. Flash flooding
entered some homes in Port Macquarie, and the Kendall and Upper Rollands Public
were closed when it was feared roads would be cut.
Manning: An average of 115mm fell across the catchment
in the 24 hours to 9am with rain easing after noon. The river peaked at 5.9m
at Wingham with minor flooding and 2.6m at Taree at midnight this evening
with minor flooding.
Williams: Around 90mm fell in the 24 hours to 9am across
the northern Hunter, causing minor flooding in the Williams system. Dungog
peaked at 6.90m at 1pm with minor flooding. Mill Dam Falls peaked near 6.7m
Colo: Minor flooding is likely to have occurred in the
Colo River at Putty on Friday, based on the Upper Colo River level which
peaked near 8.4m on Friday morning.
Sydney: Minor wind damage resulted in 50 to 60 calls to SES,
including a tree that crushed six cars at St Ives Primary School.
South Coast: A tree falling on powerlines in Wollongong about
2pm plunged 428 shops and offices along Crown Street, the main street, into
darkness for 90 minutes. Other power outages occurred at Lake Heights and Wombarra.
closed at Berry and Kembla Grange by flash flooding, while
also experienced flash flooding.
Namoi: With over 100mm falling in the lower Namoi Valley in the 30 hours to 8am, minor
flooding occurred at Wee Waa (Glencoe) with a peak around 6.3m on Friday
afternoon. The town of Pilliga was isolated, and Namoi SES had
two helicopters supplying provisions to isolated rural properties and the
Gwydir: Over 100mm of rain was recorded in the lower Gwydir
Valley and the Horton River catchment in the 24 hours to 6am. The Horton
peaked at Rider at 4.2m at 9am. The Gwydir peaked at Gravesend at 7.58m
around 5pm with minor flooding and at Pallamallawa at 6.65m around 1am Friday
minor flooding. The Mehi River (an ana branch of the Gwydir) peaked at
Moree at 5.85m in the early hours of Friday with minor flooding from local
Gwydir at Yarraman Bridge peaked at 6.29m at 7.30am Friday with minor flooding.
Tycannah Creek, just south of Moree, cut the Newell Highway and many local
roads were blocked. The Newell was also cut by flooding between Dubbo and Gilgandra.
NT: Cold morning
in the north
Overnight minima were unusually cool in the Top End this morning, especially
in the west. Wave Hill's 2.4 was 9.2 below the average, while Victoria River
Downs and Katherine were both 8.6 down on normal with minima of 3.6 and 5.4
respectively. Darwin's low of 16.1 was just 3.9 below average, but was still
the coldest morning so far this year