Characteristics of Cloud Ice and Precipitation during Wintertime Storms over the Mountains of Northern Colorado

Abstract

Abstract This article describe cloud ice and precipitation process in 17 wintertime storm systems that occurred over the mountains of northwestern Colorado. Surface, remote sensing and aircraft measurements are used to study cloud and precipitation characteristics. Ice particle concentrations; secondary ice particle production; and ice panicle growth, habits and aggregation are studied in the context of cloud system structure. The region of the cloud near cloud top was found to be a primary source region for ice particles in these clouds. Ice particle concentrations were found to increase over elevated topography and to increase at lower altitudes in deep cloud systems. Approximately 80% of the measured concentrations were within the range of 1-100 L−1, and 50% were less than 20 L−1. The activity of three secondary ice particle production mechanisms was evaluated. Fragmentation was found to be important in cloud systems that contained dendritic crystals. Evidence suggested that the Hallett-Mossop rime spl...