Meteorological aspects of the Boorabbin (WA) Fire

28 December 2007 - 8 January 2008 (see full pdf report 2.2MB)

Summary

A fire in and around the Boorabbin National Park between Kalgoorlie and Southern Cross started on 28
December 2007 and continued until 8 January 2008. In total the fire burned an area approximately 40,000
hectares in the National Park and in adjacent bushland. Tragically, three people died on the evening of 30
December when two vehicles were engulfed in flames on the Great Eastern Highway.

Overall, the conditions in the months before the fire were typically dry and warm. Despite a period of cooler weather in early to mid-December, very hot and dry conditions were a feature of the weather in the days leading to the start of the fire and then for most of the duration of the fire event. In particular, extreme fire weather conditions occurred on the day the fire commenced (28 December) and on 30 December - the
day the fire spread across the Great Eastern Highway engulfing the vehicles and causing the fatalities.

On 30 December very hot, dry northerly to westerly winds fanned the fire during the day. The temperature reached a maximum of 45.2°C at Southern Cross at about 1650 Western Daylight Savings Time (WDT), the third highest December temperature recorded at Southern Cross since observations commenced in 1908. The combination of very hot, dry and windy conditions resulted in the Fire Danger Rating being in the Extreme range for an almost continuous period from 0940 WDT until 1940 WDT. A southwesterly wind change occurred between 1930 and 2100 WDT that changed the path of the fire towards the highway. By 2100 WDT the observed southerly winds at Southern Cross had increased to above 35 km/h peaking at 52 km/h with gusts to 67 km/h at 2200 WDT. This also brought cooler and more moist conditions, the temperature falling to 27.6°C and the humidity rising above 40 per cent by 2200 WDT. Although the temperature fell and the humidity increased, the Fire Danger Rating remained Very High until 2240 WDT owing to the strength of the wind.

At the request of the Department of Environment and Conservation the Bureau of Meteorology issued 26 'spot forecasts' during the fire event in addition to the routine fire weather forecasts. On 30 December spot forecasts were issued at 0913 and 1709 WDT. These forecasts were remarkable in their accuracy; correctly indicating the extreme fire weather conditions during the day and the south southwesterly wind change expected at approximately 1900-2000 WDT.