Mountain Water Supply Forecast Summary

As of May 1, 2007, for the period between May and September 2007, Alberta Environment is forecasting natural runoff volumes to be above average for the North Saskatchewan, Red Deer, upper Bow and Kananaskis River basins, average for the Elbow and Highwood River basins, below average to average for the Oldman River basin, and below average for the Milk River basin (Table 1). Forecasts have increased compared to last month's forecasts for the North Saskatchewan, Red Deer and Bow River basins, and decreased for the Oldman and Milk River basins.

Mountain snow accumulations as of May 1, 2007 in the upper Bow, Red Deer and North Saskatchewan River basins are much above average. Snowpack to the south declines to above average in the Elbow and Highwood River basins, and below average in the Oldman River basin. Snow accumulation for the year is essentially complete.

As a result of melting of large snowpacks and wet soil conditions, natural runoff volumes recorded during March and April were above to much above average in most areas of the North Saskatchewan, Red Deer, Bow and Oldman River basins. In the Milk River basin, natural runoff volumes recorded so far have been generally below average.

As a result of the near record snowpack, there is a high risk of significant runoff in the mountain areas of the upper Bow, Red Deer, North Saskatchewan, and Athabasca River basins. High streamflows are likely, mainly within the Banff and Jasper National Parks, depending upon when and how quickly the snow melts. Alberta Environment will be monitoring these areas closely, and will issue advisories as necessary.

Future precipitation could have a major impact on all the water supply forecasts between now and the end of September. Streamflow volume forecasts will be updated monthly until mid-summer. Check our Forecaster's Comments throughout the month for updated information regarding runoff conditions.