Background
Lismore is a city of about 43 000 people located in the Northern Rivers district of New South Wales.
Lismore has a long history of flooding, with over 100 floods recoded since 1846. There have been 19 floods greater than 9.7 metres (the major flood classification) and five greater than than 10.95 metres. The highest recorded flood was in 1954 when a height of 12.27 metres was reached.
A levee, opened in mid 2005, protects the CBD from around half of all floods. Another levee protects South Lismore. North Lismore has no levee protection.
Rainfall and river rises
Heavy rain began to fall across the Northern Rivers late Wednesday 18 January as the result of a trough and deep moist onshore airstream. Heavy rain fell along the coast with orographic enhancement resulting in some very large totals of rain in the hinterland to the west of Ballina and Mullumbimby, with several locations recording 24 hour totals close to 250mm. During Thursday the 19th of January rainfall was heaviest in Lismore which recorded 170mm to 9am Friday (most in the period from 9am until 5pm). Rain eased substantially overnight Thursday 19 January with falls generally below 40mm.
At 6:55am Thursday morning the Bureau of Meteorology (BoM) issued a severe weather warning for possible flash flooding. At 7:21am a Flood Watch was issued for the possibility of flooding in the Tweed, Wilsons and Brunswick Rivers. A severe weather warning for localised flash flooding was also issued. A flood watch is a BoM product to alert people living or working in riverine areas of the possibility of flooding and to give them time to make preparations for that possibility. The flood watch caused SES volunteers and staff based in the Richmond Tweed SES Region (headquarters in Lismore) to begin preparations for the possibility of flooding. This included ensuring there were adequate human and physical resources should flooding occur including 'opening up' operations centres at the Lismore SES Unit and at the Division Headquarters in Goonellabah. It also involved liaising with local media to get out safety and preparedness messages to the public. In particular rural property owners were encouraged to move animals and equipment (such as pumps) to higher ground.
Continued heavy rain during Thursday resulted in river rises occuring on the Wilsons River and its tributaries. These enabled the BoM hydrology unit to make calculations as to the effect of the rain on stream volumes and to issue a Flood Warning at 10:53am. At that time the Wilsons River in Lismore was at 0.28 metres. The initial prediction was flood to reach the 'minor' flood class and reach 5 metres at 10pm.
Further heavy rain during Thursday resulted in this warning being revised to 6.5 metres at 4:10pm. At this time the river at Lismore was at 3.33 metres. This warning was again revised at 7:13pm with the predicted height revised upwards to 7.2 meters (moderate flooding) by midnight and possibly reaching 9.7 metres (major flooding) by 6am provided high rainfall rates continued. At this time the river in Lismore was at 4.66 metres. As a height of 9.7 metres could result in evacuations of properties in North Lismore and numerous road closures, the revised peak resulted in the State Operations Centre at SES State Headquarters in Wollongong opening up for 24 hour staffing. The region headquarters in Lismore and the Lismore unit were by now also running on 24 hour operations.
By 10:00pm rain rates eased greatly and a fourth flood warning was issued at 10:26pm revising the flood peak down to 7.2 metres at around 6am. At this time the river in Lismore was at 5.34 metres.
At 2.24 am Friday a fifth warning was issued. This also predicted a height of 7.2 metres at 6am. At this time the river was at 6.31 metres. At 4:54 a slight revision to 7.5 metres at around noon was made. Although rain rates remained generally low overnight, higher than expected flows from some tributaries caused another upwards revision of the height in a warning issued at 8:59am. This predicted a peak near 8.5 metres at 6pm. At that time the river at Lismore was at 6.85 metres. The severe weather warning was withdrawn around this time reflecting the easing in weather conditions.
A further warning at 1:30pm revised this height back down to around 8.0 metres to be reached early afternoon. At this time the river in Lismore was at 7.84 metres. After this time the river progressively fell, the peak having been reached around 2pm.
Effects
The achieved peak height of 7.85 metres was within the moderate flood classification with generally minor effects on Lismore. These included the closure of a significant number of roads in the rural areas around the city as well as several within the city boundaries. Being school holidays there were no effects on schools or school buses which in several locations would have been significantly affected.
During the course of the flood the Lismore SES received close to 100 requests for assistance. These included rescue, evacuation, media enquiries, liaison with other organisations, reading of gauges, reconnaissance of flooded areas, doorknocking residents in low lying areas and attending to people with leaking roofs requiring temporary repairs (using tarpaulins) to prevent further damage. Because of the possibility of further rain residents of North Lismore were asked from late Thursday to prepare their properties for possible flooding. No evacuation was eventually required as heights did not reach the earlier prediction of 9.7 metres. In low lying rural areas close to the city several property owners did evacuate.
Localised flash flooding around Lismore during Thursday saw several local road closures and a rescue by SES volunteers of two men from a vehicle trapped in flood waters in Wyrallah Road to the south of Lismore.
In the village of Nashua to the east of Lismore an overdue pregnant woman was airlifted by the Westpac helicopter to Lismore hospital. Near Lismore, well-known entertainer Jade Hurley was rescued after his vehicle became stranded in flood waters.
The rescue of Hurley shows the dangers of driving through floodwaters. Hurley was driving near Binna Burra, approximately 20km south-west of Byron Bay, when his motor home was hit by a sudden surge of water. Hurley was trapped in his motor home for over an hour before he was rescued by a police officer and a Rural Fire Service volunteer using an inflatable boat. Hurley was taken to nearby Byron Bay Hospital and treated for hypothermia and concussion.
At Rous to the north west of Lismore, Police rescued a woman and 5 children from flood water. The SES also had plans in place should resupply of isolated property owners be necessary.
In large operations such as this, the SES receives assistance from numerous other organisations. These include the New South Wales Fire Brigade, Rural Fire Services, Lismore City Council and NSW Police. In such a densely settled rural region road closure enquiries are significant. State road conditions are posted on the RTA website, with local roads on the Lismore City Council website.
