CR 63:171-190 (2015)  -  DOI: https://doi.org/10.3354/cr01291

ABSTRACT: Accurate assessment of snowfall patterns in high-elevation remote areas is essential to providing a foundation for further climatological analyses. The Southern Appalachian Mountain (SAM) region of the eastern US provides a unique study area due to its low latitude and proximity to the Gulf of Mexico and Atlantic Ocean. Major snowstorms, such as the remnants of Hurricane Sandy in October 2012, can result in heavy snowfall of 100 cm or greater in favorable upslope regions. Understanding the behavior of these precipitation patterns is important due to flooding threats caused by a combination of factors including deep snowpack exposed to heavy rainfall, cloud immersion, and high dew point temperatures, further exacerbating flooding threats. To contribute to this understanding, we installed the Mobile Precipitation Research and Monitoring (MOPRAM) station at Roan Mountain (1875 m) on the Tennessee/North Carolina border in October 2012. MOPRAM allowed us to analyze liquid equivalent precipitation, new snowfall, snow depth, air temperature, and relative humidity at high temporal resolutions during the 2012-2013 snow season. We present the observed snowfall event characteristics (e.g. new snowfall, liquid equivalent precipitation, atmospheric conditions, and synoptic patterns) along with how these characteristics compare to other sites in the SAM. In our 25 event dataset, we observed the following patterns: conditionally unstable upstream lapse rates; predominantly northwest winds; high-to-low elevation precipitation enhancement near a factor of 3; and 364 mm of snow liquid equivalent on Roan Mountain. An estimated 391 cm of snow fell at Roan during the 2012-2013 season using nearby snow liquid ratios as an estimate for snowfall.

KEY WORDS: Orographic snowfall · New snowfall properties · Southern Appalachian Mountains