The characteristics of precipitation observed over Cypress Mountain during the SNOW-V10 campaign

Cypress Mountain, north of Vancouver, is a 1440-m high coastal barrier for moisture-laden onshore airflow and is consequently subject to substantial precipitation. Unprecedented data from various precipitation events were obtained between January and April 2010 during the SNOW-V10 (Science of Nowcasting Olympic Weather for Vancouver 2010) field campaign occurring in conjunction with the 2010 Winter Olympics. Information was collected from specialized radar, enhanced surface weather stations, and operational observing systems. During this period, overall precipitation amounts were similar to long-term averages. Some precipitation events lasted ≥ 24 h, although periods with heavier precipitation rates lasted ≤ 6 h. Temperatures were generally above 0 °C at an observation site near the base of the mountain so snow was almost entirely absent, which was sometimes the case at other sites higher and nearer its peak. Precipitation amounts from some events were similar at the base and near the summit but other events showed much more precipitation at higher elevations. Most of these latter cases were linked with strong, sustained upward particle velocities on the upwind side of the mountain and this flow was also suggested to be a contributing factor for freezing rain occurring near the peak on occasion.