Fri Sep 20 08:33:42 UTC 2024: ## Wildfires Alter Snowpack, Impacting Water Supply in the US West

**Fort Collins, Colorado** – A new study from Colorado State University reveals how severe wildfires at high elevations are dramatically altering snowpack in the US West, jeopardizing water resources for the region. Researchers focused on the 2020 Cameron Peak Fire, analyzing its impact on snowmelt rates and timing across different slopes.

The study, published in Water Resources Research, found that the location of snowpack within mountainous terrain is crucial to its melt rate. South-facing slopes, which receive more sunlight, experience faster snowmelt and peak water content earlier in the season compared to north-facing slopes. This difference is exacerbated by wildfires.

“The loss of forest canopy lowers the amount of thermal energy in burned areas, keeping snowpack colder in winter,” explains Dan McGrath, a co-author of the study. “However, the energy balance flips in spring, with burned areas receiving significantly more solar radiation due to the lack of tree cover, leading to faster snowmelt.”

The study also revealed the importance of albedo, or reflectivity, in influencing snowmelt. Ash and soot from burned trees darken the snow, reducing its albedo and accelerating melt. While soot and ash play a role, the research found that the lack of tree canopy, which prevents solar energy from reaching the snow, is the dominant factor in accelerating snowmelt.

“This improved understanding of the energy balance is critical for water managers,” says lead author Wyatt Reis, now a research civil engineer for the Army Corps of Engineers. “It will help us develop better models and tools to predict water availability in the future.”

However, the long-term implications of these altered snowmelt patterns are concerning. South-facing slopes, often left barren and dry after wildfires, may struggle to regenerate vegetation, hindering the watershed’s recovery.

“When you consider the increasing frequency and severity of wildfires across the western U.S., particularly in high-elevation areas with deep snowpacks, this becomes a significant issue for water resources,” emphasizes McGrath. “This research provides the framework for improving our understanding and management of this crucial resource.”

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