Water Supply Outlook May 2016

Updated: May 11, 2016

Mountain runoff forecasts (natural volumes for March to September 2016)

Milk River basin

Oldman River basin
  • Much below average for Oldman River near Brocket for the March to September period
  • Below average for St. Mary River, Waterton River and Oldman River at Lethbridge for the March to September period
  • Average for Belly River for the March to September period
  • Much below average for Waterton River and Oldman River near Brocket and at Lethbridge for May to September
  • Below average for St. Mary River and Belly River for May to September
  • March-April recorded volumes are above average

Bow River basin
  • Below average for the Spray River, Kananaskis River and Elbow River for the March to September period
  • Much below average for the Bow River at Banff, Cascade Reservoir, Bow River at Calgary and the Highwood River for the March to September period.
  • Below average for the Spray River and Elbow River for May to September
  • Much below average for the Bow River at Banff, Cascade Reservoir, Kananaskis River, Bow River at Calgary and the Highwood River for May to September
  • March-April recorded volumes are average to much above average

Red Deer River basin

North Saskatchewan River basin
  • Much below average for Lake Abraham and Brazeau Reservoir the March to September period
  • Below average for North Saskatchewan River at Edmonton for the March to September period
  • Much below average for May to September
  • March-April recorded volumes are above average for Lake Abraham and North Saskatchewan River at Edmonton and below average for Brazeau Reservoir

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 May 1, 2016:

  • Oldman River basin: Much below average; ranges from 0% at Josephine Lower, Many Glacier and Westcastle II to 72% at Gardiner Creek; the average of the 11 sites is 42%.
  • Bow River basin: Much below average; ranges from 0% at Mist Creek and Wilkinson Summit to 78% at Katherine Lake; the average of the 17 sites is 49%.
  • Red Deer, North Saskatchewan, Athabasca River basins:

    Much below average for the Red Deer River basin: 2 sites are Gable Mountain at 20% and McConnell Creek at 0% of average.

    Much below average for the North Saskatchewan River basin: ranges from 0% at Job Creek to 60% at Golden Eagle; the average of the 6 sites is 35%.

    Much below average for the Athabasca River basin: 2 sites are Marmot-Jasper at 29% and Sunwapta Falls at 0% of average.

  • 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 (issued in March and April each year)

Plains Snowpack (issued in March and April each year; Cypress Hills mid to late January and February)

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 as of May 2, 2016 is available here.

Long Lead Precipitation Outlooks

Environment Canada (issued on April 30, 2016): Temperatures is forecast to be above normal across the entire province for the May through July 2016 period. Precipitation is forecast to be normal for Alberta, excluding the extreme north east corner and central portions of the province which are above normal, for the May through July 2016 period.

National Oceanic and Atmospheric Administration (NOAA) (issued on April 21, 2016): Above normal temperatures for southern Alberta for May to July 2016 and an equal chance of below normal, normal or above normal precipitation for May to July 2016.

Climate indicators: The NOAA reported on April 14, 2016 that a transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with an increasing chance of La Niña during the second half of the year.

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 and Parks
Phone: (780) 427-8636