Late season snowfalls at the end of March have improved spring runoff conditions in Saskatchewan, even as moisture levels in many areas of the province remain below, or well below normal levels.
In its latest spring runoff update on Friday (see map below), the Saskatchewan Water Security Agency said a mid-March snowstorm increased the expected additional runoff volumes to some degree across southern Alberta and southwestern Saskatchewan.
Much of this area across both provinces was snow free prior to the storm, the report said, adding that how quickly the snow melts will impact how much additional runoff will be experienced. With the area being so dry prior to the snowfall event, if a slow melt occurs, a lot of the water will infiltrate into the soil, it said. Another snowstorm in late March brought 5 to 15 cm of snow across most of eastern Saskatchewan, with the heavier snow falling in the northeastern portions of the grain belt.
A decent snowpack still exists in the Assiniboine Basin. In this area, ice layers were present during the snow surveys done at the end of February, and with the additional snow received over the past month, a near normal runoff is still expected.
The current snowpack accumulation in the Rockies currently varies significantly from well below to near normal, the report said, with the amount of runoff depending on the timing of the melt event, as well as May and June rains. These rains can quickly change the conditions in the basin. However, based on the current snowpack in the mountains and the low water supply levels in Alberta, there is a higher probability that the inflows into Lake Diefenbaker this spring and summer “will be below normal.”
Meanwhile, above freezing temperatures throughout the middle of March resulted in snowmelt runoff either beginning, or in some instances being complete, over much of southern Saskatchewan.
