Water Supply Outlook April 2010

Updated: April 15, 2010

Mountain runoff forecasts (natural volumes for March to September 2010)

Forecasts have decreased for the Milk, Oldman, Bow and the Red Deer River basins since March 1 by a significant amount at some locations. North Saskatchewan River basin forecasts are similar to March 1 forecasts.

Milk River basin Oldman River basin
  • Below average, below to much below average for the St. Mary and Belly River basins
  • Below average for April to September, much below average for the St. Mary and Belly River basins
  • March recorded volumesbelow average
Bow River basin
  • Varies from below average to much below average
  • Varies from below average to much below average for April to September
  • March recorded volumes below to much below average except above average in the Elbow and Highwood River basin
Red Deer River basin North Saskatchewan River basin
  • Below average for the Brazeau Reservoir, below to much below average for the Bighorn Reservoir and the North Saskatchewan River at Edmonton
  • Below average for the Brazeau Reservoir, below to much below average for the Bighorn Reservoir and the North Saskatchewan River at Edmonton for April to September
  • March recorded volumes much below average for the Brazeau reservoir, above average for the Bighorn reservoir, and below average for the North Saskatchewan River at Edmonton

Precipitation can have a major impact on water supply between now and the end of September. The forecasts above assume that precipitation over the remainder of the winter period and through the summer will be normal. The range of possible precipitation scenarios is large however, and as a result, probable range forecasts and a minimal precipitation forecast of natural runoff volume are also provided for each individual basin. Since more information becomes known over time, forecast ranges will narrow. Streamflow volume forecasts are updated monthly from February to May, and again in July.

Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.

Mountain snowpack

Snow accumulations measured in the mountains as of April 1, 2010:

  • Oldman River basin: Below average to much below average.
  • Bow River basin: Below to much below average upstream of Banff and in the Kananaskis River basin. Much below average in the Elbow and Highwood River basins.
  • Red Deer, North Saskatchewan, Athabasca River basins: In general, below average to average in all three basins, except below to much below average in foothill areas.
  • Upper Peace River basin in British Columbia: 65 to 100% of normal at most locations as indicated in British Columbia's Snowpack and Water Supply Outlook

Mountain snowpack is an important source of water supply to reservoirs in the spring. Accumulation at this time of year typically accounts for about 80-95% of the seasonal total.

Plains Spring Snowmelt Runoff Forecasts

Conditions are variable across the province, please refer to the map in the Plains Runoff Forecast section of our Maps and Data Summaries webpage.

Plains snowpack

  • Snow course measurements were taken at the end of March and the beginning of April in many areas of central and northern Alberta.
  • Environment Canada map of satellite estimation of plains snow water equivalent (SWE) as of March 31, 2010 is shown here.
  • Alberta Agriculture publishes maps of modelled plains snow accumulations and accumulations as compared to normal.

Precipitation

Contoured maps of precipitation amounts and as a percent of normal for the past month and for current and recent seasons are available here. Maps of precipitation amounts for the most recent day, week and month to date are available here.

Soil Moisture

Alberta Agriculture models soil moisture for non-mountainous, agricultural areas of Alberta. Modelled soil moisture compared to average as of April 4, 2010 is available here.

Long Lead Precipitation Outlooks

Environment Canada (issued on April 1, 2010): Above normal temperature and normal precipitation for Alberta for the April through June 2010 period.

National Oceanic and Atmospheric Administration (NOAA) (issued on March 18, 2010): An even chance of below normal, normal or above normal temperature and precipitation in southern Alberta, for April through June 2010.

Climate indicators : The NOAA reported on April 8, 2010 that El Nino is expected to continue in the Northern Hemisphere for Spring 2010 and transition to ENSO neutral conditions for Summer 2010.

Note that forecasting weather for such a long time period into the future is very difficult, and so the historical accuracy has been variable, dependent on location and time period, and is often low, more so for precipitation than temperature. Environment Canada provides an assessment of their forecast method's historical accuracy on their website.

Reservoir storage

Water storage volumes in the major irrigation and hydroelectric reservoirs of the Milk, Oldman, Bow, Red Deer North Saskatchewan, and Athabasca River basins is updated each weekday and is available in the Provincial Reservoir Storage Summary.

Questions

Background information on the Water Supply Outlook is available in Frequently Asked Questions

Media Contact:
Communications Division, Alberta Environment
Phone: (780) 427-6267