Modeling climate-fire connections within the Great Basin and Upper Colorado River Basin, Western United States

The Great Basin and Upper Colorado River Basin of the Western United States possess complex topography and varied fire ecology. The specific precipitation and temperature patterns that may increase the likelihood of fire occurrence and severity in this region are poorly understood. This study used antecedent climate patterns to identify the conditions prior to fire occurrence and to construct a model of fire risk and severity for the Interior Western United States. Data from the Monitoring Trends in Burn Severity (MTBS) dataset spanning a period from 1984 to 2009 were used to understand spatial and temporal trends in fire. Parameter-elevation regressions on independent slopes model (PRISM) data were used to represent climatic conditions across the study area during this time period, based on monthly maximum temperature, precipitation and drought severity. These data revealed five fire-climate patterns which exist within the region; three of the patterns are characterized by predominantly dry conditions and two by predominantly wet conditions during the months prior to a fire. Maximum entropy modeling was used to characterize the spatial patterns of fire-climate classes and predict future fire conditions, and classification trees were used to examine burn severity. A test dataset of fires which occurred within the study region during 2010 were predicted with an average area under curve (AUC) score of 0.945. Results from modeling burn severity were less robust, but do provide a risk assessment based on current and antecedent climate conditions. This modeling approach is aimed at providing land managers a practical way to assess current and future fire conditions at a relatively fine spatial scale given the current infrastructure and availability of climate data.