Burn Probabilities

An optional output grid from the minimum travel time fire growth model.

This feature produces a single output map that contains the fraction of the number of fires that encountered each node (0.0 to 1.0). These are conditional probabilities, which come with several assumptions.

• A fire has started, or given a fire start this is the probability that a given node will burn.
• Each random fire burns under the same specific set of conditions fuel moistures, weather, wind, and fixed duration of active fire spread.
• This output gives no indication of the probability of a fire starting.

High burn probabilities are related to the sizes of fires that occur on a given landscape - for the same conditions, large fires produce higher probabilities than small fires (each burn a larger fraction of the landscape). Since fire size is a function of the gross spread rate and duration of the fire, treatments or conditions that reduce the spread rate will lower the burn probability.  

The burn probabilities calculated by FlamMap use static fuel moistures and winds for the entire burn period. Unlike FSPro or FSim which assign different fuel moistures and winds for each burn day.