Local scale variability in storm snowfall and seasonal snowpack distributions in the Bridger Range, Montana

Synoptic and regional estimation of snow water equivalent often uses a sparse network of elevation-stratified snow measurements. The interpolation of such data on meso- and local scales has seldom been tested. Individual storms and April 1st snowpack were measured during the 1994-95 winter near Bozeman. Montana to assess geographic and meteorologic factors influencing meso- and local scale snowfall and snowpack distribution and its variability. A network of eleven measurement sites was established east of Ross Pass in the central Bridger Range. Results showed that the regional April 1st snow-elevation gradient predicts local scale gradients but a local scale gradient did not predict the regional scale. For storm distributions, elevation was significantly correlated in 50% of storms. Distance east of the ridge was significant in 81% of storms, and was more strongly correlated in six of the eight storms where elevation was also significant. However, because of strong covariance, partitioning these two signals was not possible and thus, either variable is a reasonable linear predictor of snow distributions in this study. Snowfall distributions were classified using hierarchical cluster analysis which identified four storm classes. Snow distributions in the Ross Pass area resemble distributions generated by small-scale barrier models.