PRELIMINARY EVALUATION OF SNOW ACCUMULATION PATTERNS BASED ON STORM TYPE, MAMMOTH MOUNTAIN, CALIFORNIA 1996 - 2001

This study examined snow accumulation at 8 sites in the subalpine zone on Mammoth Mountain, California, over the course of 67 storms during the winters 1996-1997 through 1990-2001. Locations of the field sites resulted from considering the tradeoffs between avoiding areas subject to snow erosion or wind deposition and selecting sites that exhibited little mass loss due to interception by forest canopy. The sites ranged over 500m in elevation and occurred on aspects from the east to the north-northwest side of Mammoth Mountain. Observations of snow accumulation consisted of snow depth and density measurements from snow boards, representing storm total accumulations. Measurements from the snow boards were taken at the end of each storm cycle. Synoptic variables from standard charts published by the National Weather Service formed the basis of classif~,ing storms into four types: 1) mid-latitude front, 2) zonal, 3) cutoff or continental low and; 4) split flow. Measurements from the snow boards were related to similar observations made at a reference site by the Mammoth Mountain Ski Patrol. The analyses used regression analyses assuming linear models to evaluate trends in the accumulation measurements due to different storm types. The analyses showed that for most storms, snowfall exhibits strong correlation for specific storm types over scales of hundreds to thousands of meters, the range of distance between the sites. Storm-wise correlation among sites showed that different storm types exhibited different loading patterns. Results suggest that consideration of storm category could affect the type of interpolation one could use when dealing with operational station data.