Critical threshold for crossing a firebreak: mathematical model and fire experiments

Firebreaks are commonly used to limit the spread of wildfires towards sensitive areas. However, the risk of extreme fires increases the likelihood that suppression capacities will be exceeded. This study proposes an effective design framework for firebreaks, based on the estimation of the probability of crossing as a function of fire behaviour and weather conditions. A risk matrix is established to support decisions. The probability of crossing is calculated using logistic regression, with data from several bushfire experiments. The results show that a probability greater than 35% indicates a high risk of crossing, while a probability less than 25% indicates a moderate risk. Above 45%, the risk becomes severe. By estimating the risks, we can improve the design and maintenance of firebreaks to make them safer and more effective.