This data set contains 12-hour manual new snow and liquid precipitation equivalent (LPE) observations collected at the Alta-Collins (CLN) snow-study plot during the 2000–2023 cool seasons (October 1–April 30 with the year defined by the ending calendar year). CLN is located mid-mountain at Alta Ski Area in the Wasatch Range of northern Utah (approximately 111.63889W, 40.57607N) at an elevation of 2945 m.
Detailed ground-based observations of snow are scarce in remote regions such as the Arctic. Here, Multi-Angle Snowflake Camera (MASC) measurements of over 55,000 solid hydrometeors — obtained during a two-year period from August 2016 to August 2018 at Oliktok Point, Alaska — are analyzed and compared to similar measurements from an earlier experiment at Alta, Utah. In general, distributions of hydrometeor fall speed, fall orientation, aspect ratio, flatness, and complexity (i.e., riming degree) were observed to be very similar between the two locations, except that Arctic hydrometeors tended to be smaller. In total, the slope parameter defining a negative exponential of the size distribution was approximately 50% steeper in the Arctic as at Alta. 66% of particles were observed to be rimed or moderately rimed, with some suggestion that riming is favored by weak boundary layer stability. On average, the fall speed of rimed particles was not notably different from aggregates. However, graupel density and fall speed increase as cloud temperatures approach the melting point.
