Below normal to near normal spring runoff forecast for the Southwest

Widespread snow across the Southwest this past week will have an impact on potential runoff amounts this coming spring.

According to the Water Security Agency’s Preliminary Spring Runoff forecast released on February 6, the Southwest is in the region where below normal to near normal runoff conditions existed as of February 1.

The Water Security Agency preliminary runoff outlook noted that conditions over most of southern Saskatchewan were dry before freezeup. And while the lower portion of the Southwest had normal fall precipitation, available depressional/wetland water storage volumes remain high because of the dry conditions experienced over the summer. Top soil moisture conditions were described as being short to very short at freeze-up across most of southern Saskatchewan.

Early winter snowfall in the lower portion of the Southwest was generally at normal rates, but the windy weather and losses during early 2019 may not accurately represent the runoff potential.

“This is particularly true for many areas where the snowpack was almost completely melted or sublimated due to periods of well above normal temperatures,” the report notes. “However, this meltwater would have wetted the soil surface, reducing the infiltration capacity available for the melt of any late season snow.”

An area which generally runs along the Transcanada Highway through the Southwest shows that early winter snowfall was generally 60 to 85 per cent of average.

The Water Security Agency reported that the majority of long range precipitation forecasts are calling for near normal precipitation over the coming weeks. These seasonal models are also predicting warmer than normal conditions.

With below or well below normal snowmelt runoff expected in the spring of 2019, it is anticipated that there could be some agricultural water supply shortages similar to 2018. These issues will likely intensify and expand across southern Saskatchewan. This could also create some surface water supply issues for municipalities and irrigators if conditions remain dry into the summer months.

Unless conditions change significantly, WSA will be aggressive in storing water during the snowmelt runoff period to ensure water supplies are adequate and lake levels are desirable for recreational uses through 2019. The Water Security Agency will be issuing their Spring Snowmelt Forecast in early March.