Cobaw Escaped Burn – April 2003.

The summer of 2002-03 had been one of the largest and most prolonged fire seasons for many years. Huge bushfires spread across the Victorian Alps, NSW and even into some Canberra suburbs where four people died and over 500 homes were lost.

People and communities were angry and several state and federal government inquiries were announced.

Many bushfire “experts” were running commentary in the press with renewed allegations that a lack of Fuel Reduction Burning (FRB) on public land had contributed to the extent of the summer bushfires.

In the first week of April 2003 the Department of Sustainability and Environment (DSE) had conducted 59 FRBs across the State, all without incident.

Most firefighters were becoming fatigued, and the summer crews were nearing the end of their annual employment contracts.

It was against this backdrop that on Friday morning, 4 April 2003, staff from DSE together with colleagues from Parks Victoria (PV), ignited an approved 650 ha Fuel Reduction Burn in the Cobaw State forest north of the Macedon Ranges.

The burn was planned and led by an experienced Fire Management Officer (FMO) from Bacchus Marsh.

The weather pattern was leading into a typical autumn drying cycle and was within prescriptions. Most of the area hadn’t been burnt since 1965 and the ground and elevated fuels were at extreme levels. The thick stringybark on the messmate trees (E. obliqua) presented a particular hazard.

The local CFA brigades were notified, but it was not customary for them to participate in routine burns on State forest.

A test burn was lit at 09.30 am and ignition was attempted throughout Friday morning but was terminated around midday because of the slow progress and damp fine fuels from a shower of rain earlier in the week. However, the underlying soil and fuel dryness was still high with a Kettch-Byram Drought Index well above 100.

The DSE and PV crews returned home in the late afternoon and patrols were arranged over the weekend with an intention of returning early on Monday morning to complete the job.

It was not uncommon to leave Fuel Reduction Burns unattended overnight, particularly if they were within containment lines and during autumn when the nights were cool and followed by a morning dew.  This conserved crews for daylight work when they could be more effective.

On Saturday morning around 10.00 am an experienced Park Ranger from Macedon went on patrol as planned. Also rostered that weekend were the Fire Duty Officers at Bacchus Marsh and Ballarat that took responsibility for coordination of burns across the region.

The burn had continued to trickle slowly over Friday night but remained sluggish, so efforts were made during Saturday morning to consolidate boundaries and bring the burnt edge out to containment lines and roads.

Forest fuels have a long residual burning time and don’t extinguish quickly or easily like grass. This adds considerably to the complexity and length of the firefighting effort, particularly patrol and blackout.

The fire behaviour escalated steadily throughout Saturday afternoon with some flare ups and spotting around 6.30 pm as the fuels dried out. But as expected, the fire quietened down again later in the evening.

However, because of the fire behaviour on Saturday, additional crews and bulldozers were deployed early on Sunday 6 April to cut-off the fire boundary on Camp Track.

But by mid-afternoon the weather worsened, and the fire spotted over Camp Track and threatened the safety of a D4 bulldozer operator.

The fire behaviour then intensified with high rates of spread and flames climbing into the tree crowns. The smoke column, measure by the radar at Tullamarine airport, reached 4000 m.

At the same time as the spot over of Camp Track an empty parked car was discovered on Ridge Road and two hikers were believed to have made their way to an old lookout which was in the direct path of the fire. Crews were deployed to find the couple without success so backburning was commenced to stop the spread of the fire towards the lookout area.

Despite all the fire activity during the afternoon the fire was still within the original planned containment lines at 7.30 pm on Sunday evening, and fire behaviour quiet, when all crews left the bush.

The experienced Officer In Charge reasonably believed that the fire would once again die down overnight and intended to return with a full complement of vehicles and crew on Monday to complete the task.

But during the middle of the night the fire unexpectedly began to spread downhill over two kilometres under the influence of northerly winds and a dry air mass sitting at altitude above the fire.

Surprisingly, the Cobaw State forest sits up high at an elevation of 650 m, which was above the temperature inversion layer that developed on Sunday night. This meant that the bush remained dry and warm while the paddocks and nearby farms on the lower flats received fog and a light dew.

The fire was reported in private property at 05.00 hrs on Monday morning 7 April 2003 and a joint DSE/CFA incident management team was deployed to control the escape.

The 1339 ha fire burnt 360 ha of private property to the south causing slight damage, but also threatened some houses. It took months to rebuild fences and settle all compensation the claims with landholders.

There was considerable criticism of DSE by media commentators, armchair experts and the local community. Disappointingly, some other firefighters joined the noisy chorus while the smoke was still swirling and before the investigation had even begun.

Two internal reviews were conducted leading to some changes to procedures. Importantly, the Chief Fire Officer Gary Morgan, apologised to the community but remained resolute in his support for the staff and crews.

It was found that the main things that contributed to the escape were the complexities of the site and seasonal conditions, the underlying drought, the heavy fuels, particularly the messmate bark. Lighting over three days was not originally planned so crews became caught up in a rapidly drying cycle that saw the fire intensity increase more than expected. Not being able to cut the burn off at Camp Track, the two hikers and the unanticipated temperature inversion of Sunday night played a big role. Not having enough crews to leave online overnight to patrol was also a significant factor.

Fuel Reduction Burning is inherently risky and requires great skill and courage, as well as a generous dollop of good fortune, to execute successfully.

It’s one thing to be an outside observer, or even a firefighter holding a drip torch, but quite another to plan a FRB and approve “dropping the match” and then take full responsibility for its success, or failure.

The escape at Cobaw later became the subject of a senior fire leadership training program called a Staff Ride.

Top Photo: The fire escaped after it crossed Camp Track on Sunday afternoon. Photo: Lee Gleeson

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