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Summary and implications of Report: Victorian 2009 February Fires

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This summary and discussion of the implications of the report has been compiled by the conservation groups. The Report it refers to analyses the driving influences of the February 7 fires and looks at how the fires passed through and affected different areas of land.

Influences of the Victorian fires of February 2009

This summary and discussion of the implications of the report has been compiled by the conservation groups. The Report it refers to analyses the driving influences of the February 7 fires and looks at how the fires passed through and affected different areas of land.
Download the full report here (PDF 6.2MB) >>

A catastrophic event

The fires of 7 February 2009 have been described as Australia’s worst natural disaster in 100 years.  They claimed more lives and destroyed more property than any fires documented in this country.  The fires started on a day of unprecedented bushfire danger following a fortnight of record-breaking temperatures and in the midst of the longest drought on record.

In the week following 7 February environment groups extended the deepest sympathy to those affected by the tragedy.  Many friends and supporters were killed, lost loved ones or were left homeless.  In addition to the human cost, these intense bushfires had a significant impact on our environment and will continue to do so for many years to come.  Environment groups believe we must do everything in our power to avoid a repeat of these devastating fires.  This means implementing the Royal Commission’s 51 recommendations and examining planning and urban growth issues across the state. It means re-assessing logging practices and fuel-reduction burning strategies. It also means taking urgent action on climate change, as scientists warn climate change is bringing hotter and drier weather to south-eastern Australia, together with more extreme heatwaves and heightened fire danger.

Catastrophic conditions


The McArthur Fire Danger Index (FDI) rating system takes account of four factors: temperature, relative humidity, wind speed and ‘drought factor’.  Traditionally the FDI has used a scale up to 100 with danger levels described as:

  • Moderate         5 to 12
  • High               12 to 25
  • Very high        25 to 50
  • Extreme         50 to 100


After one of the driest and hottest Januarys on record, the scene was set in February 2009 for Victoria to experience higher FDIs than ever before.  At 3pm on 7 February relative humidity was 9 per cent and wind gusts reached 81 km/h.  These factors, combined with a high ‘drought factor’, saw the Bureau of Meteorology forecast an FDI of 142 for forests and 186 for grasslands. 

The conditions recorded on Black Friday in 1939 effectively set the Forest Fire Danger Index benchmark of 100.  But the fire danger levels on 7 February 2009 are believed to have significantly exceeded the previous records set on 13 January 1939 (Black Friday) and 16 February 1983 (Ash Wednesday).  Conditions above 50 have traditionally been described as ‘extreme’.  The unprecedented 2009 conditions have prompted the need for a new category – ‘catastrophic’ – to describe fire weather conditions that exceed 100 FDI.

The emergence of ‘catastrophic’ fire weather must change the way we prepare for future fire seasons.
 
How effective is fuel reduction burning in catastrophic conditions?

McCarthy and Tolhurst (2001) have shown the benefits of prescribed burning decrease as the Fire Danger Index increases.  They constructed a model for predicting the probability of a previous prescribed burn slowing the front of a subsequent bushfire. McCarthy and Tolhurst’s graph shows the likely effectiveness of fuel reduction burning – up to a FDI of 100.  As the Fire Danger Index exceeded 100 on 7 February, the graph has been extrapolated to provide an indication of the effectiveness of prescribed burns under the catastrophic conditions on Black Saturday.

The graph indicates that during catastrophic FDIs the probability of previous prescribed burns slowing a bushfire front is vastly reduced. On 7 February, the FDI at Kilmore Gap was calculated to be 190. At an FDI of 190, it is unlikely the fuel-reduction burns previously carried out in the area had any affect in slowing the fire, considering the extrapolation from the above graph. Although the extrapolation exceeds the limits of data analysis to date, it does provide a broad indication of expected trends at catastrophic FDIs.

The fire severity mapping of the Black Saturday fires show that areas previously treated with fuel-reduction burns were severely affected in the catastrophic conditions of Black Saturday and burned at a very high severity rate (see Map 5.2 on page 3 for an example).  The McCarthy/Tolhurst model together with the fire severity maps from 7 February, suggest that the effectiveness of prescribed burns are greatly reduced under catastrophic FDI conditions.

What is the role of native vegetation clearance for catastrophic conditions?

Most of the fires on 7 February started on private property and then spread into plantations, state parks and National Parks.

The majority of the land affected by fire on 7 February had experienced moderate to significant human disturbance through the removal of native vegetation, urban development or logging. Based on the mapping analysis conducted by the report author using DSE Fire and Land Tenure Map overlays, approximately 43 per cent of fire-affected land was state forest, 29 per cent was private land, 23 per cent was National Parks and 5 per cent was plantations.

Evidence in the report also suggests the fire progressed with greater severity through highly modified rural landscapes and areas where native vegetation had been removed or significantly reduced, than through older ecologically mature tall forested stands such as those in the Wallaby Creek catchment in the Kinglake National Park.  The fire’s progress also became patchy when it entered the wet eucalypt forests of the Yarra Ranges National Park under reduced fire weather conditions later in the day. 

This evidence suggests fuel-reduction burns and the clearing of vegetation and firebreaks will not prevent the spread of fires under catastrophic weather conditions and should only be considered as one part of a broader fire management strategy.

Climate change

In January/February 2009 records were set for maximum temperatures, number of consecutive days over 35°C, low levels of relative humidity, low levels of fuel moisture content resulting from extended periods of low rainfall in fire affected areas.  University of Melbourne Professor David Karoly believes it is highly likely changing climatic patterns are influencing the frequency and intensity of high fire danger days in south-eastern Australia. Climate change modelling by CSIRO and the Bureau of Meteorology is consistent with this prediction.

Report conclusions

A number of key issues and observations are made in this report that are relevant to the
Royal Commission’s investigation on land management for the protection of life, property and the environment:

  • Most fires started on private land
  • The area burnt across Victoria comprised state forests (43 per cent), timber plantations (5 per cent), private land (29 per cent) and National Parks (23 per cent).
  • Fires that started on private or leased land on 7 February were uncontrollable by the time they arrived at the boundaries of National Parks (e.g. Kinglake and Yarra Ranges).
  • Fires that started within parks and protected areas (e.g. Wilson’s Promontory and Mt Riddell in Yarra Ranges National Park) were mostly contained within National Parks;  the exception being the fire in the Bunyip State Park
  • The condition of vegetation plays a significant role in the intensity and spread of fire (i.e. there is evidence fire spreads more readily in modified and disturbed vegetation)
  • Climate change is likely to be having a significant influence on droughts, maximum temperatures, the low moisture content of fuel, decreased humidity levels and an important contributing factor in the unprecedented maximum temperatures on 7 February 2009
  • The number of high, very high, extreme and catastrophic fire danger days is predicted to increase under climate change
  • The number of extreme fire danger days already exceeds those predicted to occur in 2050
  • The probability of previous prescribed burns slowing a head fire significantly decreases with increasing FFDI
  • On 7 February many areas of forest that had been treated with prescribed burns were still severely burnt because of the extreme conditions

It is recommended that the Royal Commission, fire management agencies and the community consider the above aspects of land management for fire risk, and the implications for the appropriate and effective use in mitigating bushfire risk. Reliance on any one method of fire management and/or focusing on one land tenure type could increase risk, particularly given the observations and predictions being made with the increasing intensity and frequency of fire danger days under climate change scenarios.

The report by Chris Taylor was commissioned by the Victorian National Parks Association, the Australian Conservation Foundation and the Wilderness Society and complied over the last six months. This summary draws on data from the Interim Report by the Royal Commission and supporting documentation; Department of Sustainability and Environment’s (DSE) Fire Web page; Bureau of Meteorology; NASA Earth Observatory; Media reports; on-site visits to a number of the fire affected areas; and a review of literature and interviews with fire prevention and response personnel and witnesses.

 

Further reading

Download report - Cover of February 2009 Victorian Fire Report - by Chris Taylor (PDF 6.2 MB).

Planned burns and vegetation clearing will not stop catastrophic fire events: report
Article - 10 September 2009
Prescribed burns did not significantly slow the spread of bushfire in the catastrophic conditions of Black Saturday, states a new report released on 10 September 2009. More >>

Joint Media Release
10 September 2009
Planned burns and vegetation clearing will not stop catastrophic fire events: report. More >>