Nov 2022
Will total harvest bans be more common this harvest?
Nov 2022
Will total harvest bans be more common this harvest?

Written by:

Richard Quinlan | Agronomist | 0428 648 828


The answer is probably.

This is not because conditions are any more dangerous than in previous seasons, but because the system used to assess fire bans has changed in 2022.

The Australian Fire Danger Rating System (AFDRS) changed in September 2022. This system condenses the category system to 4 categories. This is no big deal. What has really changed is the information that is used to calculate the fire danger rating. This is now driven by the Fire Behaviour Index (FBI).

How a harvest ban is calculated:
• The FBI is a numbered scale (0-100 and beyond) which is now standard across Australia. The higher the value the higher the fire danger risk.
• This scale is then divided into categories which represent a transition in fire behaviour (Figure 1).
• FBI ratings over 50 represents conditions which are too dangerous to allow harvest to continue.
• The FBI is now tailored to specific vegetation types.

Vegetation types have different structural characteristics. The number of vegetation models used in the FBI has increased from 2 to 8 (Figure 2) making them much more specific. The vegetation type for the wheatbelt is “Grassland” (Figure 2).

Figure 1: The new Fire Behavior Index (FBI) which is used to call a harvest ban. Anything over 50 is considered too high for harvesting to be allowed.

Figure 2: The 8 different models used to calculate the FBI. It is expected that this system will result in more harvest bans than the previous system used to calculate fire risk. We can only wait and see if this will be the case.

If you want a forecast of fire danger ratings then head to the BOM:

Fire weather districts:

Want to know more?



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