Mean Wind Patterns and Snow Depths in an Alpine-Subalpine Ecosystem as Measured by Damage to Coniferous Trees

Abstract

1. Deformations of Engelmann spruce and subalpine fir trees were surveyed for the purpose of determining climatic wind speeds and directions and snow depths in the Glacier Lakes Ecosystem Experiments Site (GLEES) in the Snowy Range of southeastern Wyoming, USA. Tree deformations were recorded at 50- and 100-m grid intervals over areas of c. 30 ha and 300 ha, respectively, over the GLEES. 2. The climatic mean wind speed was estimated to be 7.4 m s -1 ; the mean air flow was predominantly westerly. The snow depths ranged from less than 0.2m to 5.5m, depending on topographic features and vegetative architecture. 3. Compared with snow depth surveys, precipitation measurements, and a degree-day snow depth model, the average snow depth estimated by the tree deformation method was 70% of the long-term mean. 4. The tree deformation method was useful for detailed estimates of wind speed, wind direction, and snow depth at a fine scale in complex terrain where meteorological instrumentation and snow survey data are minimal.