Water Supply Outlook for Alberta

March 2006

Mountain Snowpack

Snow accumulations in the mountains as of March 1, 2006 generally improve moving from north to south and at higher elevations (Table 1). Measured snowpacks are generally average to above average in the Kananaskis, Elbow, Waterton and St. Mary River basins, average in the Oldman River basin, below average to average in the Bow and Highwood River basins, below average in the Red Deer River and Athabasca River basins, and below to much below average in the North Saskatchewan River basin. Late February snowfall that occurred since measurements were taken is not enough to change this significantly. The snowpack in the upper Peace River basin, in British Columbia, is generally below 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). Three locations at lower elevations (4900 to 5000ft) had values ranging from 34 to 79% of average for this time of year, which is below to much below average. For the seven locations above 6300ft the snowpacks ranged from 91 to 131% of average, above to much above average in the Waterton/St. Mary area and average to above average in the northern half of the Oldman River basin. Most of the snow courses in the Oldman River basin were taken prior to a late February snowfall event. This snowfall would generally increase the percent average snow water equivalent in Table 2 by approximately 8 to 10% of average, not enough to significantly change the status of the snowpack.

Eighteen snow courses were measured at the end of February in the Bow River basin, with values ranging from 83 to 117% of average (Table 3). In the Highwood River basin, snowpack conditions are below average to average, while in the Kananaskis and Elbow River basins conditions are generally average to above average. Snow accumulations are below average for elevations below 6700ft and average above 6700ft for this time of year in the northern half of the upper Bow River basin. Four snow course measurements in the upper Bow River basin were completed during a snowfall event on February 27, so the percent of average may be 3 to 5% higher than indicated above and in Table 3.

Four snow course measurements were taken at the end of February in the Red Deer River basin. One station at elevation 6400ft was recorded at 67% of average, which is below to much below average. The remaining three stations, at elevations above 6700ft, ranged from 81-91% of average, which is below average for this time of year (Table 4).

Four snow courses were measured in the North Saskatchewan River basin at the end of February. Two stations, above 6300ft, show the snow water equivalent to range from below to much below average, while two lower elevation stations (below 4500ft) showed snow accumulations to be much below average, at 30 and 33% of average.

In the Athabasca River basin three snow courses were taken and values ranged from 74 to 90% of average . Within the Athabasca River basin snowpack conditions appear to be slightly higher in the north, where they are below average to average. In southern portions they are below to much below average.

Snowpack in the upper Peace River basin in British Columbia is generally below average, as seen in the B.C. Snowpack and Water Supply Outlook (http://wlapwww.gov.bc.ca/rfc/river_forecast/bulletin.htm#Northeast).

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