Mountain Snowpack

Snow accumulations in the mountains as of December 1, 2006 are average to above average for this time of the year in the Oldman and Bow River basins and much above average in the Red Deer River basin. The mountain snowpack is an important source of water supply to reservoirs in the spring. On average, the accumulation of snow at this time of the year accounts for nearly one-fifth of the seasonal total.

Three snow courses and two automated snow pillow readings were taken at the end of November in the Oldman River basin, with values ranging from 92 to 127% of average for this time of year, which is average to above average (Table 1). Generally, snow accumulations are higher than in December 2004 and 2005.

Eight snow courses were measured at the end of November in the Bow River basin, with values ranging from 84 to 132% of average for this time of year, which is generally average to above average(Table 2). Generally, snow accumulations are higher than in December 2004 and 2005.

One snow pillow reading in the Red Deer River basin showed the snowpack at 185% of average on December 1, 2006, which is much above average and significantly higher than in December 2004 and 2005 (Table 3).

No snow course measurements were made in the upper North Saskatchewan or Athabasca River basins this month. More comprehensive snow course measurements of basin snowpack begin at the end of January.

Four snow pillows in the upper Peace River basin in British Columbia indicate snowpack ranging from 100 to 120% of average, as seen in the snow pillow plots available at: http://www.env.gov.bc.ca/rfc/river_forecast/snowp_map.htm.

At twelve snow course sites, real-time snow accumulation can be monitored using snow pillows. Snow pillows can be viewed by choosing any mountainous southern basin, and snow data, in the two drop down menus at:

Snow water equivalent values on the snow pillow may or may not match the snow course value at a particular location. While snow pillow data is very valuable information, the quantity of snow on the pillow is only representative of the accumulation at that specific spot. A snow course survey is measured at numerous spots and provides a more representative value of snow in the area. In some locations, there can be considerable difference between the snow pillow and snow course values. Factors such as wind and exposure of the site can cause the snow pillow values to be significantly different from the snow course survey. The snow pillow graphs on our website show the daily average snow water equivalent. The monthly snow survey is the average of all measurements conducted within five days of the end of the month. Also, where snow pillow and snow course measurements are available for the same site, snow pillow records tend to be much shorter (10-15 years) in length compared to the snow course sites. As a result, the difference in the average value between the snow pillow and the snow course can be attributed to snow water equivalent being derived two different ways (physically measured compared to an instrument reading), site location and length of data record. In some cases, the values can deviate by 10-20%. Therefore, while snow pillows are excellent for analyzing trends and for monitoring accumulation between snow surveys, snow course values should always be used when considering the quantity of snow at a particular location as they best represent that area.

Click here to see a map of snow course locations

Plains Snowpack