The father of fire-behaviour research in Australia, the late Alan McArthur, developed a scale of Forest Fire Danger Indexes that is still widely used throughout the nation. On this scale, the perceived worst possible conditions of temperature, humidity, windspeed and drought, provide an Index of 100. Ratings of 50 to 100 equate to ‘Extreme’ conditions, while below this they range from ‘Very High’ down to ‘Low’ fire danger.
In the days leading up to Wednesday 8 January 2003, the Index had been climbing. With most of eastern Australia reeling under the impact of drought, the country was primed for disaster.
On the 8th, when dry storms swept across southeastern NSW and eastern Victoria, the McArthur Index was close to the ‘Extreme’ part of its range.
Seven fires were reported near the western border of the ACT. During the next seven days the Forest Fire Danger Index dropped in Canberra to the ‘Moderate’ to ‘High’ range and winds were generally blowing the fire away from the city. But on January 16 and 17 ominous changes occurred. By the afternoon of the 16th in Canberra the Index had reached the lower margin of ‘Very High’ and on Friday 17th it was near the upper edge. On Saturday 18 January the Index hit the very top of McArthur’s scale.
Last updated 4 November 2014