According to the province's latest spring flood outlook, released this morning, there is now a major risk of flooding along the Red River, and low to moderate risk of flooding in most Manitoba basins. Recent precipitation events south of the border in the United States are the main factor for the flood risk on the Red increasing. Winter precipitation has been well above normal in the U.S. portion of the basin, and below normal on the Manitoba side.
Under the normal and unfavourable weather scenarios, the Red River is forecast to exceed its banks full capacity from Emerson to Morris.
The province’s practice is to plan and prepare for the unfavourable future weather condition scenario, which is a weather scenario that would have a 1-in-10 chance of occurring from now until the spring run-off. Under that scenario, levels on the main stem of the Red River would be similar to 2020 from Emerson to Red River Floodway Inlet. Even under an unfavourable scenario, community dikes and individual flood protection works are higher than predicted peak levels.
Operation of the Red River Floodway is expected this spring to reduce water levels within Winnipeg, and operation of the Portage Diversion is also anticipated to prevent ice jamming on the Assiniboine River east of Portage.
Spring flooding risk is generally low along the Souris, Roseau, Rat and Pembina rivers.
Under unfavourable future weather condition scenario, there is moderate risk downstream of Minot along the main stem of the Souris River, with levels similar to the 2013 spring levels. The existing dikes in Melita, Souris, and Wawanesa are high enough to protect against these flood levels.
Meanwhile, there is a low to moderate risk of significant spring flooding along the Assiniboine River. With unfavourable weather conditions, levels would be similar to 2015 from the Shellmouth dam downstream to Brandon.
The Hydrologic Forecast Centre noted, as in many other years, the risk could change in any river basin depending on weather conditions between now and the spring