Water Supply Outlook for Alberta
April 2008
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 is nearing the
seasonal total in the Oldman River basin and is normally 80 to 95% of the seasonal
total in mountain areas north of this basin.
Eight snow courses and two automated snow pillow readings were taken at the end of March
in the Oldman River basin, with values ranging from 81 to 129% of average. Generally the snowpack
is above average in the St. Mary, Waterton, and Belly River basins. The Crowsnest and
Castle River basins recorded mostly average to above average snowpack, whereas the upper
Oldman River basin stations recorded below average to average snowpack conditions.
(Table 2).
Seventeen snow courses readings were taken near the end of March
in the Bow River basin, with values ranging from 77 to 101% of average
(Table 3).
In the Highwood and Elbow River basins conditions are generally
below average. Snow accumulations in the Kananskis River basin are below average to
average. Upstream of Banff, snow accumulation is generally average to
below average. At one snow course location in the upper Cascade River basin,
snowpack conditions were measured at below to much below average.
Four snow course measurements were taken at the end of February in the Red Deer River basin,
with values ranging from 71 to 87% of average. Snow accumulations are generally below
to much below average for this time of year, ranking third to ninth lowest in 25 to 30
years of record
(Table 4).
Four snow courses were measured in the North Saskatchewan River basin at the end of February.
Snow water accumulation ranged from 71 to 119% which is below average to average on the whole.
In the Athabasca River basin three snow courses were taken. The two locations in the mountains
recorded snow water equivalent from 83 to 91% of average which is average to below average
for this time of year. The lower elevation station at Hinton recorded 145% of average which is
above to much above average snowpack.
Snowpack in the upper Smoky River basin in British Columbia recorded snow water equivalents
from 107 to 111% of normal which is average to above average.
Snowpack in the upper Peace River basin in British Columbia is generally 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
Mountain Snowpack
Snow accumulations in the mountains as of April 1, 2008 are generally higher in
the southernmost and northernmost basins and lower in the central basins
(Table 1).
Measured snowpacks are generally average to above average in the Oldman River basin,
below average to average in the Bow River Basin, below to much below average in the Red Deer River basin,
mostly below average to average in the North Saskatchewan River basin,
average in the Athabasca River basin, average to above average in the Smoky River basin and above average
in the Peace River basin.
For technical enquires about
this web page please contact
Alberta Environment - Environmental Management
Water Management Operations Branch at
AENV-WebWS@gov.ab.ca
