Microphysical structure and evolution of a central Sierra Nevada orographic cloud system

Abstract

The cloud system extended 130km upwind of the Sierra Nevada crestline, was 4km deep, had a base temperature of +5°C, and a top temperature of ~-15°C. Cloud droplets rising from cloud base grew to sizes >50μm and first encountered dendritic ice particles descending from cloud top over the middle elevations of the Sierra Nevada. Within this region, rapid removal of the large droplets by riming occurred, and secondary ice-crystal production due to rime splintering was observed. Needles produced by secondary ice-particle production were incorporated into dendritic aggregates falling from cloud top farther toward the mountain crest. -from Author