Fire weather and large fire potential in the northern Sierra Nevada

Fuels, weather, and topography all contribute to observed fire behavior. Of these, weather is not only the most dynamic factor, it is the most likely to be directly influenced by climate change. In this study 40 years of daily fire weather observations from five weather stations across the northern Sierra Nevada were analyzed to investigate potential changes or trends in the frequency of high- to extreme-fire weather. The analysis demonstrated fairly strong upward trends in the occurrence of high- to extreme-fire weather, particularly since the mid-1990s. This increased occurrence of high fire weather conditions suggests that there is more opportunity for fires to grow rapidly and overwhelm initial suppression efforts, likely resulting in greater incidence of large fires throughout the region. This is particularly problematic in the northern Sierra Nevada, where there is a complex arrangement of land ownerships, including numerous human communities.