Water Supply Outlook for Alberta

January 2004

Mountain Snowpack

Snow accumulations in the mountains as of January 1, 2004 are generally below-average to average for this time of the year. The mountain snowpack is an important source of water supply to reservoirs in the province. On average, the accumulation of snow at this time of the year accounts for 40 to 50% of the seasonal total.

There were a limited number of snow course measurements taken at the end of December. More comprehensive measurements of mountain snowpack begin at the end of January.

One snow course and three automated snow pillow readings were taken at the end of December in the Oldman River basin, with values ranging from 67 to 103% of average for this time of year (Table 1). Snow accumulations are below-average to average and are generally much better than those observed on January 1 of both 2003 and 2002.

Seven snow courses and one automated snow pillow reading were made at the end of December in the Bow River basin, with values ranging from 77 to 113% of average (Table 2). Snowpack measurements vary from below-average to above-average for this time of year, but generally the basin snowpack is near average. Snow accumulations are generally much higher than those observed last year at this time and similar to those recorded in January 2002.

Two snow pillows in the Red Deer River basin show accumulations of 106 and 114% of average on January 1, which is slightly above-average for this time of year (Table 3). Snow accumulations are less than those observed last year at this time at Limestone and much much greater than those measured last January at Skoki. Snow measurements are similar to those taken on January 1, 2002.

No snow course measurements were made in the upper North Saskatchewan or Athabasca River basins this month.

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

Satellite estimation of plains snowpack as of January 1, 2004 is available in Figure 1. Snowpack around Calgary has been overestimated by the satellite. Weekly updates to the satellite maps are available on the Meteorological Survey of Canada website . More detailed information on plains area snowpack will appear in the March Water Supply Outlook as plains snow course measurements will be conducted at the end of February.

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