Wildfires are among the most widespread and impactful disturbances of ecosystems and have been increasing in frequency, severity, and size in many parts of the world. Forest fires can fundamentally affect watershed hydrology by restructuring the vegetative community and architecture. Topography is an important factor in snowpack accumulation and ablation as it determines exposure to solar radiation and atmospheric conditions. Few direct measurements of post-fire snowpack have been taken and little is understood about how fire affects snowpack characteristics or how it interacts with topography. To observe these trends we set up a full factorial experiment on the Twitchell Canyon fire in south-central Utah which included both north and south facing aspects and burned and unburned forest conditions.
Results/Conclusions
We found that wildfire had an opposite effect on snow depth and density depending on aspect. Deeper snowpack was found on northern facing burned aspects and shallower snowpack on southern facing burned aspects when compared with unburned forests on the same aspect. While there were differences in snow depth and density, there was no observed difference in snow-water equivalence (SWE) between burned or unburned forests. We also observed faster rates of ablation on both north and south facing burned aspects. These findings have multiple implications for snow-water resources and management downstream. Further work is necessary to determine energy balances in burned forest and in various topographic positions as well as calculating springtime evaporation, soil infiltration, and large-scale watershed responses to fire in high elevation subalpine systems.