Whistler Mountain climatology: Temperature lapse rates in complex terrain

Temperature lapse rates on highly sloping terrain deviate greatly from those expected over idealized flat surfaces due to the effects of shading, aspect, and localized channeling through valleys. At Whistler, British Columbia, the installation of a wide array of meteorological instrumentation in connection with 2010 Winter Olympics has created an unprecedented opportunity to investigate such phenomena. Here, we conduct a set of observations designed to examine temperature structure with a high resolution profile of temperature and humidity sensors installed on the mountain slope. The goal of this research is to characterize mountainside lapse rate profiles under various synoptic and seasonal conditions. A secondary objective is to investigate the relationship between mountainside temperature profiles and mid-mountain cloud formation; an acknowledged problem for ski operations on Whistler Mountain.

Instrumentation used consists of five Environment Canada weather stations and two weather stations run by Whistler Mountain, both of which are further supplemented by the installation of five Hobo data loggers in order to provide higher resolution temperature and relative humidity measurements in the zone critical to the analysis of mid-mountain cloud formation. In addition to these automated systems, a series of web cameras will provide visual verification of cloud formation while a ceilometer will measure cloud base heights. Initial results will be presented from the complete array of instrumentation, emphasizing how this project will aid in a forecaster's ability to predict an upcoming low-visibility event which impacts safe management of ski hill activity.