Water Supply Outlook for Alberta

March 2007

Mountain Snowpack

Snow accumulations in the mountains as of March 1, 2007 generally improve moving from north to south and at higher elevations (Table 1). Measured snowpacks are generally below average in the St. Mary River basin, average to above average in the Waterton, Belly, Oldman, Elbow and Highwood River basins, above to much above average in the upper Bow, Kananaskis and North Saskatchewan River basins and much above average in the Red Deer and Athabasca River basins. The snowpack in the upper Peace River basin, in British Columbia, is generally well above average. 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 three-quarters of the seasonal total.

Eight snow courses and two automated snow pillow readings were taken at the end of February in the Oldman River basin (Table 2). Two locations at lower elevations (4900ft), in the St. Mary River basin, had values of 65 and 85 % of average for this time of year, which is below average. The remaining eight stations had values ranging from 94 to 117 % of average, which is average to above average for this time of year.

Sixteen snow courses were measured at the end of February in the Bow River basin, with values ranging from 100 to 145% of average (Table 3). In the Elbow and Highwood River basins conditions are generally average to above average, while in the upper Bow and Kananaskis River basins snowpack conditions are above to much above average.

Three snow course measurements were taken at the end of February in the Red Deer River basin, with values ranging from 131 to 144% of average, which is much above average for this time of year (Table 4). All values ranked in the top five out of approximately 25 years of record.

Four snow courses were measured in the North Saskatchewan River basin at the end of February. Three stations, above 4400ft, show the snow water equivalent to range from 111 to 142% of average, which is generally above to much above average. The lower elevation station (3500ft) had a value of 77% of average which is below average.

In the Athabasca River basin three snow courses were taken and values ranged from 131 to 165% of average, which is much above average for this time of year. Values ranked from second to eight highest in up to 36 years of record.

Snowpack in the upper Peace River basin in British Columbia is generally well above average, as reported in the B.C. Snowpack and Water Supply Outlook http://www.env.gov.bc.ca/rfc/river_forecast/bulletin.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

For technical enquires about this web page please contact Alberta Environment - Environmental Management Water Management Operations Branch at AENV-WebWS@gov.ab.ca