Mountain Snowpack

Snow accumulations in the mountains as of March 1, 2005 generally improve moving from south to north (Table 1). Measured snowpacks are much below average in the Oldman River basin, below average to average in the Bow River basin, above average in the Red Deer River basin, average in the North Saskatchewan River basin, and above average to much above average in the Athabasca River basin for this time of the year. Snowpack in the upper Peace River basin, in British Columbia, is generally 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.

Thirteen snow courses and two automated snow pillow readings were taken at the end of February in the Oldman River basin. Values range from 15 to 93% of average for this time of year, not including five locations which do not have a long enough period of record (Table 2). Snowpacks at all elevations showed little improvement during the past month and remain generally much below average. Record lows were measured at three of four locations below 6000 feet of elevation, one fewer than last month. Four locations above 6000 feet of elevation had snowpacks ranging from 62 to 66% of average, ranking among the lowest five on record in up to thirty-six years of data, and two northern locations near the divide with the Bow River basin were below average to average for this time of year at 88 and 93% of average.

Sixteen snow courses were measured at the end of February in the Bow River basin, with values ranging from 67 to 105% of average (Table 3), a decrease from last month. Snow accumulations are below average to average for this time of year upstream of Banff, and in the Elbow and Highwood River basins. The Kananaskis and Spray River basins have generally below average snow accumulations.

Seven snow course measurements in the Red Deer and North Saskatchewan River basins show accumulations ranging from 84 to 122% of average on March 1, 2005, and three snow course measurements in the Athabasca River basin range from 114 to 162% of average (Table 4). Snowpack is average for this time of year in the North Saskatchewan River basin, above average in the Red Deer River basin, and above to much above average in the Athabasca River basin. The Hinton snow course ranked second highest in thirty-one years of record.

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

Although snowfall was heavy during the first ten days of February, accumulations since have been minimal on snow pillows in the upper Red Deer, Bow and Oldman River basins. Further snow course measurements will be conducted at the end of March.

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