Manitoba Transportation and Infrastructure’s Hydrologic Forecast Centre reports the risk of spring flooding is low to moderate for most Manitoba rivers heading into the spring runoff period, with the exception of the Fisher River basin in the Interlake Region which has a moderate to major flood risk.
Spring flood risk remains largely dependent on weather conditions from now through the melt period, including additional snowfall, spring rainfall and the timing and rate of snowmelt. The Hydrological Forecast Centre advises most Manitoba lakes are expected to remain within their desired operating ranges after spring runoff and the risk of flooding along Manitoba lakes is low. A moderate risk of flooding is in effect for the Red, Assiniboine and Souris rivers along with the Icelandic River in the Interlake region and portions of the Saskatchewan River in northern Manitoba.
Spring flood risk is moderate to major along the Fisher River. Flood risk is considered low for the Red and Assiniboine River tributaries, including the Pembina, Rat and Roseau rivers. Eastern Manitoba including the Winnipeg River basin and Whiteshell Lakes area and most Manitoba lakes also have a low risk of spring flooding.
Soil moisture at freeze-up was near-to below-normal across most of Manitoba, winter precipitation has ranged from near-to below-normal in many regions and soil frost depths are generally normal to shallower than normal, allowing normal to above-normal infiltration of meltwater.
Snow-water content across Manitoba basins indicated snow accumulations are generally within the normal range, except for parts of southern Manitoba where snow accumulation remains below typical values for this time of year. The Fisher river basin in the Interlake region has normal to above-normal snow water content.
Lake levels across the province are within their operating ranges. Lake Winnipeg and Lake Manitoba are well below normal for this time of year and inflows into most major lakes are expected to be below seasonal normals, reflecting generally drier-than-normal conditions across contributing river basins.
The Red River Floodway is not expected to be operated under normal or favourable weather conditions but may be operated under unfavourable conditions to reduce water levels within the City of Winnipeg. The Portage Diversion may be operated under unfavourable weather conditions or to mitigate ice-jamming on the lower Assiniboine River. The Shellmouth Reservoir is being operated in consultation with the Shellmouth Liaison Committee to reduce downstream flood risk while maintaining water supply and recreation objectives.
Ice-cutting and breaking activities are complete along the Red River and Icelandic River to reduce the risk of ice-jam flooding. There is a risk of jam induced flooding in areas that are historically affected by ice jams, including the Saskatchewan, Carrot, Swan, Icelandic and Fisher rivers.
Ice conditions and spring weather will play a key role in determining breakup timing and localized flooding potential.
Spring flood risk will continue to depend on weather conditions through the melt period. As temperatures warm and ice strength deteriorates, Manitobans are reminded to stay off waterways, rivers and retention ponds.
The Manitoba Emergency Management Organization continues to work with local authorities, First Nations and emergency management partners to prepare for potential spring flooding. This includes reviewing emergency plans, sharing information, and preparing resources for flood response, as well as coordination with Indigenous Services Canada and Manitoba Municipal and Northern Relations for First Nations and northern communities.
