- Title:
-
Bushfire Weather Climatology of the Haines Index in South-western Australia
- Date:
- March 2007
- Organisations
- Bureau of Meteorology
- Authors:
- L. McCaw, P. Marchetti, G. Elliott and G. Reader
- Location:
- Australia, WA, Australia
Overview
The climatology of bushfire weather as measured by the Haines Index (HI) was examined at four locations in southwestern Australia. The HI is determined by the stability and moisture content of the air in the lower atmosphere and is provided as a routine component of fire weather forecasts in the United States.
High values of the HI (6) were found to be most frequent during the summer months of December and January, and were more frequent at Perth and Kalgoorlie than at Albany or Esperance. Days of moderate (5) or high (6) HI were associated with higher median values of the McArthur Grassland Fire Danger Index (GFDI) and were more likely to have a fire danger rating of extreme (GFDI ≥ 50). Days of very high fire danger (32 ≤ GFDI < 50) occurred at all values of the HI.
The fact that extreme values of GFDI are strongly associated with high HI suggests that the current fire danger rating system based on surface-level weather conditions already identifies the majority of days with significant fire growth potential. Case studies of fires that burnt strongly when the GFDI was high or very high could assist in establishing whether the HI has a discernable effect on fire size or severity under these conditions.
