POST-FIRE DEBRIS FLOW PREDICTION MODELS AND DECISION MAKING AT THE WILDLAND URBAN INTERFACE OF BOISE, IDAHO

Hazards associated with fire are exacerbated at the wildland urban interface, where confronting the realities of larger, more severe fires and a prolonged fire season includes considering the increasing risk of fire related disasters such as fire-induced debris flows. Recently developed models predict the probability and resulting volume of post-fire debris flows (Cannon et al., 2010). These models have pre-fire decision-informing capacity, but are almost exclusively applied after fire to make land management decisions under a more limited time frame than pre-fire application would allow. The City of Boise, Idaho is currently creating a detailed wildfire risk assessment to identify and communicate diverse, fire-related hazards to its citizens. Boise has not undertaken a post-fire debris flow hazard assessment, despite having both a written and geologic history of these potentially deadly events. Boise’s efforts to complete a wildfire risk assessment offer the ability to bring post-fire debris flow models into the pre-fire stages of the decision-making process, thus extending the timeline over which potentially life-saving decisions can be made.

Having the ability to predict post-fire debris flow response is valuable when planning to mitigate the effects these hazards may have on life and property. However, current predictive models (Cannon et al., 2010) are not often used in a pre-fire decision-making setting, and their utility under these circumstances is unclear. Therefore, we seek to understand how these models are used in a pre-fire decision-making setting as an important step to determine how other communities can effectively use these models in the future. Presented here is our ongoing work with the City of Boise to use post-fire debris flow models and recognize their potential and limitations to inform decisions regarding protection, conservation and restoration efforts within the Boise foothills and, more broadly, the wildland urban interface of the present and future.