Mountain snowpack response to different levels of warming

Area of Science:

• Climatology
• Hydrology
• Environmental Science

Background:

• Mountain snowpack is a critical source of freshwater globally.
• Temperature variability directly influences snowpack distribution and persistence.
• Warmer temperatures lead to decreased snow water equivalent (SWE) and higher elevation snowpack centroids.

Purpose of the Study:

• To quantify the impact of increased winter air temperature on Sierra Nevada snow water equivalent (SWE) volume and centroid.
• To assess the probability of exceeding long-term average SWE and centroid elevations under various warming scenarios.
• To analyze regional variations in SWE response to warming across the Sierra Nevada.

Main Methods:

• Utilized a multivariate probabilistic framework.
• Simulated the effects of 1.0 to 2.0 °C increases in winter air temperature.
• Analyzed changes in 1 April SWE volume and its centroid elevation.

Main Results:

• A 1.0 °C warming reduced SWE volume probability by 20.7% and increased centroid elevation probability by 60.6%.
• Higher temperature increases (1.5-2.0 °C) led to greater SWE volume reductions and centroid elevation increases.
• Northern Sierra Nevada showed higher hydrologic vulnerability to warming compared to the southern region.

Conclusions:

• Projected increases in mountain temperatures will likely intensify observed changes in SWE.
• The Sierra Nevada snowpack is highly sensitive to winter warming, with significant implications for water resources.
• Regional differences in SWE response highlight the need for localized adaptation strategies.