Oral Presentations
Presentation Type
Presentation
Faculty Mentor’s Full Name
Joel Harper
Faculty Mentor’s Department
Geoscience
Abstract / Artist's Statement
A high-confidence effect of anthropogenic climate change is an increase in the frequency and intensity of extreme weather events. One type of these events which is important to western Montana is midwinter rain, or rain on snow. In coastal states, where the mountain snowpack sits near the melting point, rain on snow can cause massive melt and flooding and diminish the snowpack residents rely on for drinking water and hydroelectric power when it melts in the spring. In Montana, however, the snowpack is typically much colder and more resistant to the devastating effects of these events. The purpose of this research is to investigate rain on snow events in Montana and their effect on the mountain snowpack. How do these events change the water content, cold content, and spring meltout of the snowpack, and how do these effects vary with elevation? To quantify these changes, the research focused on a large rain event in January 2021, which delivered up to 2 inches of water equivalent to the Missoula and Flathead valleys. Data were analyzed from snow telemetry (SNOTEL) stations across the region and reconciled against snowpack observations from local avalanche forecasting centers. Although sparse and incomplete data often make assessment of the instantaneous conditions at a location ambiguous, the data show very clear time/space trends as the event evolved. The SNOTEL stations show a much different picture than what would be expected from a warmer snowpack. Low elevation sites show an obvious loss of water content, but higher elevations show a small or even significant increase, likely due to the higher cold content of the snow and its capacity to absorb and refreeze rainwater. Ground observations show a widely distributed crust from this refreezing, which could alter the way the snowpack behaves in the subsequent spring.
Category
Physical Sciences
How Does Midwinter Rain Affect Western Montana’s Mountain Snowpack?
UC 330
A high-confidence effect of anthropogenic climate change is an increase in the frequency and intensity of extreme weather events. One type of these events which is important to western Montana is midwinter rain, or rain on snow. In coastal states, where the mountain snowpack sits near the melting point, rain on snow can cause massive melt and flooding and diminish the snowpack residents rely on for drinking water and hydroelectric power when it melts in the spring. In Montana, however, the snowpack is typically much colder and more resistant to the devastating effects of these events. The purpose of this research is to investigate rain on snow events in Montana and their effect on the mountain snowpack. How do these events change the water content, cold content, and spring meltout of the snowpack, and how do these effects vary with elevation? To quantify these changes, the research focused on a large rain event in January 2021, which delivered up to 2 inches of water equivalent to the Missoula and Flathead valleys. Data were analyzed from snow telemetry (SNOTEL) stations across the region and reconciled against snowpack observations from local avalanche forecasting centers. Although sparse and incomplete data often make assessment of the instantaneous conditions at a location ambiguous, the data show very clear time/space trends as the event evolved. The SNOTEL stations show a much different picture than what would be expected from a warmer snowpack. Low elevation sites show an obvious loss of water content, but higher elevations show a small or even significant increase, likely due to the higher cold content of the snow and its capacity to absorb and refreeze rainwater. Ground observations show a widely distributed crust from this refreezing, which could alter the way the snowpack behaves in the subsequent spring.