Water Security Agency
May 11, 2023

Heavy Rainfall Advisory for Southeast Saskatchewan

A Colorado Low is expected to move into the southeastern corner of the province overnight tonight. This system is expected to remain relatively stationary into Saturday, resulting in appreciable precipitation accumulations. South of Highway 1, general accumulations of 40 to 60 millimetres (mm), about 1.5 to 2.4 inches, are expected from Coronach east to the Manitoba border with the highest accumulations near the US border. Localized accumulations may approach 80 mm (approximately 3 inches) where imbedded thunderstorms result in heavier downpours. 

There is the potential for localized flooding and high streamflow in areas where rainfall intensities and accumulations are highest. There is also an increased risk within areas where soil moisture levels remain high and storage available within wetlands is low following the melt of the April 19/20 snowfall event. This includes upper portions of the Souris River Basin from Rafferty Dam to Bechard and upper portions of the Long Creek Basin near Radville.

While Boundary, Rafferty, and Grant Devine reservoirs are all at or near their full supply levels, there is additional flood storage available at Rafferty and Grant Devine reservoirs that WSA is prepared to use to reduce flows downstream on the Souris River. The Boundary to Rafferty Diversion Channel will also be utilized to reduce, or possibly eliminate, the need for releases from Boundary Dam. As such, we are not expecting flows on the Souris River downstream of these dams to exceed channel capacities as a result of this event.

The Water Security Agency (WSA) advises the public to take precautions near water bodies as flows can change quickly. If you see areas of high flow, please keep your distance.

In the event where a situation exceeds the coping capacities of the local authority or where the local authority requires extra support and/or resources, the Saskatchewan Public Safety Agency (SPSA) can provide additional assistance. SPSA can be reached by calling 1.800.667.9660, and further information on submitting a request for assistance can be found here.

WSA also advises communities at risk of imminent flooding can access support with the Emergency Flood Damage Reduction Program (EFDRP). The EFDRP provides financial, engineering and technical support to evaluate the potential flood risk to buildings and to identify options to mitigate the risk when flooding is imminent. Services include client discussions, site visits, hydrological and other technical evaluations, developing mitigation recommendations and cost share funding for permanent flood defenses and temporary relief through pumping.

WSA will continue to monitor conditions and provide updates.

For more information, please contact:

Sean Osmar