Item: Effects of Bark Beetle Attacks on Snowpack and Snow Avalanche Hazard
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Title: Effects of Bark Beetle Attacks on Snowpack and Snow Avalanche Hazard
Proceedings: International Snow Science Workshop 2016 Proceedings, Breckenridge, CO, USA
Authors:
- Michaela Teich [ Utah State University, Department of Wildland Resources, Logan, UT, USA ]
- Martin Schneebeli [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Peter Bebi [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Andrew D. Giunta [ Utah State University, Department of Wildland Resources, Logan, UT, USA ]
- Curtis A. Gray [ Utah State University, Department of Wildland Resources, Logan, UT, USA ]
- Michael J. Jenkins [ Utah State University, Department of Wildland Resources, Logan, UT, USA ]
Date: 2016-10-02
Abstract: Unprecedented bark beetle outbreaks across western North America have resulted in the death of millions of trees, which profoundly affects snowpack in high elevation forests. Healthy, dense forests growing in avalanche terrain reduce the likelihood of avalanche release by inhibiting the formation of continuous weak layers, which are key for slab avalanche formation. Bark beetle outbreaks quickly change composition, structure, and functions of forest ecosystems and may alter the protective effect of forests against snow avalanches. We examined the snowpack under canopies of Engelmann spruce forest stands in the central Rocky Mountains in Utah, USA, using the SnowMicroPen (SMP). Biweekly-repeated SMP measurements along 20 m transects at 0.5 m intervals were recorded in winter 2015/16 in study plots beneath canopies of a recently infested trees (green), trees 3+-years after bark beetle infestation (gray), a harvested forest stand, and a non-forested meadow. We describe the evolution of the snow-pack at our four study plots with two-dimensional snow density profiles as a measure of snow stratigraphy, which we derived from our high-resolution spatio-temporal SMP data. Our results indicate that at this relatively small spatial scale, differences in snow density layers between green and gray forest stands were not clearly observable. More homogeneous layering developed during periods of less to moderate snowfall where unloading or melting of intercepted snow from the canopy is reduced and snow metamorphism is the dominant process influencing snow stratigraphy. After harvesting, canopies of remaining smaller diameter trees and woody debris had no significant impact on snow stratigraphy, which needs to be addressed when planning silvicultural measures in protection forests and ski resorts. Considering changes in snowpack properties and local wind regimes following bark beetle attack is important for road and railroad safety, winter backcountry activities, avalanche forecasting, and protection forest and ski resort management.
Language of Article: English
Presenters:
Keywords: subcanopy snow stratigraphy, avalanche protection forest, spruce beetle, SnowMicroPen
Page Number(s): 975-982
Subjects: SnowMicroPen forest avalanche snow stratigraphy
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Digital Abstract Not Available
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