Water Supply Outlook for Alberta

January 2004

Mountain Snowpack

Mountain snow accumulations as of January 1, 2003 are much-below-average for this time of year. Eleven of twelve snow measurements taken at the end of December ranged from 40 to 76% of average. The current snowpack is lower than last year at this time but is much higher than in 2001, which was the lowest on record in most areas. A late December snowfall in the southwest corner of Alberta helped increase mountain snowpack in this region, but accumulations remain much-below-average for the season. 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.

Three snow course and automated snow pillow readings were taken at the end of December in the Oldman River basin. The snowpack is much-below-average for this time of year, ranging from 40 to 76% of average (Table 1).

Seven snow courses and automated snow pillow readings were made at the end of December in the Bow River basin. Values range from 53 to 73% of average, which are are much-below-average for this time of year (Table 2).

A snow pillow in the upper elevations of the Red Deer River basin had 45% of average snowpack on January 1, 2003, which is much-below-average for this time of year. The Limestone snow pillow, in the foothills of the basin, is 115% of average, due to a localized snowfall in early October. (Table 3).

At twelve snow course sites, real-time snow accumulation can be monitored using snow pillows. Snow pillows can be viewed by choosing any 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.

Plains Snowpack

El Nino conditions have brought very warm and dry weather to the province this winter, leaving very little snow in Alberta plains areas. Satellite estimation of snow water equivalent shows plains area snowpack is much-below-average as of January 1, 2003 (Figure 1). South of Edmonton and in the Peace region, plains area snowpack is especially low, with little or no snow cover in these areas. Additional information on plains area snowpack will appear in the March Water Supply Outlook as 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