Water Supply Outlook April 2015
Updated: April 16, 2015
Mountain runoff forecasts (natural volumes for March to September 2015)
Milk River basin Corrections made to the April to September Forecast: April 16, 2015- Slightly above average to above average for the March to September period
- Average for April to September
- March recorded volumes are much above average, due to spring melt starting earlier than normal at lower elevations
- Below average for the St. Mary River, Waterton River and Oldman River at Lethbridge for the March to September period
- Average for the Belly River and Oldman River near Brocket for the March to September period
- Below average for April to September
- March recorded volumes are much above average, due to spring melt starting earlier than normal at lower elevations
- Below average to average for the March to September period.
- Below average for the Bow River at Banff, Cascade Reservoir, Elbow River and Highwood River for April to September, except for the Spray River, Kananaskis River and Bow River at Calgary which is average
- March recorded volumes are average to much above average, due to spring melt starting earlier than normal at lower elevations
- Below average for the March to September period
- Below average for April to September
- March recorded volumes are much above average, due to spring melt starting earlier than normal at lower elevations
- Below average for Lake Abraham for the March to September period
- Slightly below average for Brazeau Reservoir and North Saskatchewan River at Edmonton for the March to September period
- Slightly below average for Brazeau Reservoir and North Saskatchewan River at Edmonton for April to September, except for Lake Abraham which is below average
- March recorded volumes are average to much above average, due to spring melt starting earlier than normal at lower elevations
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, 2015:
- Oldman River basin: Much below average to below average: ranges between 0% (Lee Creek) and 94% (South Racehorse Creek) of average.
- Bow River basin: Much below average to below average: ranges between 52% (Bow River) and 100% (Wilkinson Summit Open) of average.
- Red Deer, North Saskatchewan, Athabasca River basins:
Much below average for the Red Deer River basin.
Much below average for the North Saskatchewan River basin: ranging between 60% (Brown Creek) and 122% (Southesk) of average.
Average to much above average for the Athabasca River basin.
- Upper Peace River basin in British Columbia: as indicated in British Columbia's Snow Survey and Water Supply Bulletin
Mountain snowpack is an important source of water supply to reservoirs in the spring. Accumulation at this time of year typically accounts for nearly three-quarters of the seasonal total.
Plains Spring Snowmelt Runoff Forecasts
Runoff is either complete or is expected to be much below average, please refer to the map in the Plains Runoff Forecast section of our Maps and Data Summaries webpage.
Plains snowpack
- Map of Snow course measurements 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 April 4, 2015 is shown here. The SWE in the central portion of the province was overestimated due to melting and refreezing activities.
- 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 March 31, 2015 is available here.
Long Lead Precipitation Outlooks
Environment Canada (issued on March 31, 2015): Temperatures is forecast to be above normal across the entire province for the April through June 2015 period. Precipitation is forecast to be above normal in the south of the province for the April through June 2015 period.
National Oceanic and Atmospheric Administration (NOAA) (issued on March 19, 2015): An equal chance of below normal, normal or above normal precipitation and temperatures in the province except for above normal temperatures in southern Alberta from April to June, 2015.
Climate indicators: The NOAA reported on March 5, 2015 that an El Niño Advisory is still in place. There is an approximately 50-60% chance that El Niño conditions will continue through Northern Hemisphere summer 2015.
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
