Water Supply Outlook August 2015

Updated: August 5, 2015

Mountain runoff forecasts (natural volumes for March to September 2015)

Milk River basin Oldman River basin
  • Average except for Oldman River near Brocket and at Lethbridge, which are below average for the March to September 2015 period
  • Much below average except for Oldman River near Brocket, which is below average for August to September
  • March-July recorded volumes are average except for Oldman River near Brocket and at Lethbridge, which are below average
Bow River basin Red Deer River basin North Saskatchewan River basin
  • Much below average except for Lake Abraham, which is average for the March to September 2015 period
  • Below average except for Lake Abraham, which is much below average for August to September
  • March-July recorded volumes ranges from much below average to above average

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 (issued in December to June each year)

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 compared to average as of July 31, 2015 is available here.

Long Lead Precipitation Outlooks

Environment Canada (issued on July 31, 2015): Below normal precipitation in west central portions of Alberta for the August through October 2015 period.

National Oceanic and Atmospheric Administration (NOAA) (issued on July 16, 2015): Normal precipitation in Alberta for August to October 2015.

Climate indicators : The NOAA reported on July 9, 2015 that there is a greater than 90% chance that El Niño will continue through Northern Hemisphere winter 2015-16, and around a 80% chance it will last into early spring 2016.

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