The Relationship Between Monthly Precipitation and Elevation in the Canadian Rocky Mountain Foothills

TitleThe Relationship Between Monthly Precipitation and Elevation in the Canadian Rocky Mountain Foothills
Publication TypeConference Proceedings
Year of Conference2009
AuthorsSmith, C. D.
Conference Name77th Annual Western Snow Conference
Series TitleProceedings of the 77th Annual Western Snow Conference
Date PublishedApril 2009
PublisherWestern Snow Conference
Conference LocationCanmore, AB
KeywordsOrographic precipitation, Canadian Rocky Mountain Foothills, snowpack, FOPEX

Many areas of the Canadian Rocky Mountains foothills have very sparse or no instrumentation for climate monitoring. To better monitor and understand precipitation processes in the Alberta foothills, the Foothills Orographic Precipitation Experiment (FOPEX) was initiated. FOPEX consists of six meteorological sites installed in a 40 km east-west transect between Caroline and Limestone Mountain in west-central Alberta, Canada. The sites are strategically located at elevations between 1070 and 2120 metres above sea level and were operational between October-2001 and May-2007. Regression analysis showed strong linear relationships between monthly cold season (October through April) precipitation when accumulations are not lower than 70% of the long-term average. When these conditions are met, the rate of increase of monthly precipitation with elevation is shown to be dependent on the total monthly precipitation observed. This increase with elevation is 88% for each 1000 m increase in elevation. Spatial and topographical influences on precipitation during the warm season (May through September) weaken any linear relationship with elevation but it is shown that the average increase with elevation is 38 mm/1000 m when precipitation is not lower than 70% of the long term mean but decreases to 18 mm/1000 m in drier months. A linear relationship between snowpack snow water equivalent (SWE) and elevation is also shown and is found to vary with the amount of precipitation received at lower elevations. Monthly snowpack correlations with elevation are generally weaker than for accumulated precipitation.