Water Supply Forecast Summary

A major spring snowstorm in mid-May improved the water supply condition dramatically in southern Alberta. Forecasts of water supply increased for the fourth consecutive month due to the above-normal precipitation received since January. The late spring however has resulted in little depletion of the high elevation snowpack in the Bow, Red Deer and North Saskatchewan River headwaters. The Oldman River headwaters did see some snowmelt runoff in the last week of May. As a result of the above-normal spring precipitation, near average natural runoff volumes are now forecast for a majority of the mountain rivers in the March to September 2002 period (Table 1).

As a result of the late spring, most areas in the province have recorded below-average to much-below-average natural runoff volumes for the March to May 2002 period. The late snowmelt impacts the water supply forecasts for the remaining portion of the runoff season (June to September). The remaining volume forecast (June to September 2002) is average to above-average in most areas.

June 1 forecast volumes increased from last month's forecast in all areas, with the largest increases occurring in the Milk and Oldman River basins. Current forecasted runoff is substantially (20 to 50%) higher than recorded runoff last year.

These forecasts assume that precipitation over the summer period will be normal. Precipitation will have a major impact on the summer water supply forecast 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.