Precipitation from unstable weather may result in localized overland flooding on land adjacent tributaries and streams across southern Manitoba. People living in areas susceptible to overland flooding should watch for these conditions.
Due to the wind and the deteriorating state of ice on many lakes, today’s risk of ice pileup on the shorelines of major lakes is high on Lake Winnipeg (south basin), Lake Manitoba, and North, East and West Shoal Lakes; medium at Dauphin Lake, Lake Winnipegosis, Lake St. Martin, Oak Pelican and Rock lakes; and low on the Red Deer Lake.
Flood warning are in place for the Souris River from Melita and all downstream reaches; the Assiniboine River downstream of Shellmouth Bridge to Portage la Prairie; the Pipestone Creek, all reaches; Oak Lake and Plum Lakes; and Plum Creek to the Souris River (including the town of Souris).
Flood watches have been issued for the Assiniboine River downstream of Portage la Prairie and the Qu’Appelle River in the St-Lazare area.
The Red River is cresting in Morris today. Sustained high flows are expected for a prolonged period along all reaches of the river.
Flood Response
A major storm is causing snow and rain along with high winds that are expected to shift from southerly to northerly directions across most of southern Manitoba. The slow-moving system is expected to move across Manitoba today and tomorrow. The storm will affect the dates of river crests and prolong the duration of the flood. Forecasters are assessing the storm’s impact and will have more information once it is over.
Due to high wind gusts forecast across southern Manitoba today, those properties with flood-protection works and exposed to north winds can expect wind setup and wave action and are advised to assess the need for flood-protection reinforcements.
Four rural municipalities (RMs), Cartier, St. Francois Xavier Headingley and Portage la Prairie along the Assiniboine River are raising and reinforcing dikes as a precautionary measure. Flows down the Assiniboine River are being gradually increased and will reach 18,000 cubic feet per second (cfs) by May 2. Manitoba Water Stewardship, Manitoba Emergency Measures Organization and Manitoba Infrastructure and Transportation met with the RMs yesterday. Provincial flood-barrier tubes and 40,000 sandbags are being provided to assist the RMs with raising the dikes.
Sandbags and flood-tube barriers are also being provided to the RM of Woodlands to assist with raising dikes around the Shoal Lake areas.
Gravel is being added to the road at Riverside, between Rosenort and Morris, to maintain continued access in and out of the community.
Red River Valley ring dikes continue to be pumped to keep rainwater away from the inside of their dikes.
As a precautionary measure, the Town of Minnedosa is raising and reinforcing an earth dike along the Little Saskatchewan River.
Weather is affecting operations of the STARS helicopter today. Its operations are limited as the storm tracks across the province. Areas with snow, colder temperatures and strong winds are not accessible by the helicopter today.
There are 1,911 Manitobans evacuated from their homes, mostly due to a loss of safe road access. Evacuees include 118 people from the RM of Morris, 224 people from the RM of Ritchot, 777 people from the Roseau River First Nation and 665 people from the Peguis First Nation. There are Manitobans evacuated from other areas of the province including the Brandon area and the Pinaymootang (Fairford) First Nation.
There are 90 provincial roads affected by flood waters, snow and rains as a result of the storm, 54 are closed, seven because of storm conditions. Approximately 620 municipal roads are closed. The storm will affect road conditions throughout the next two days. Travellers are advised to exercise caution, check road conditions and be prepared to take alternative routes.
Information about the federal election on Monday, May 2 is available from Elections Canada at 1-800-463-6868 or www.elections.ca.
Red River
Water levels just upstream of the Red River Floodway inlet are 763.99 ft., with flows of 75,700 cfs. Flows in the floodway are approximately 35,500 cfs. Flows above the floodway inlet will steadily increase until the peak occurs on or around May 3.
Water levels at James Avenue in Winnipeg decreased 0.22 feet since yesterday to 18.83 ft. Flows at James Avenue this morning were approximately 54,800 cfs. Flows on the Assiniboine River will be increasing in the upcoming days. In the absence of flood-protection works, water levels at James Avenue would have been 30.6 ft. or approximately 11 ft. higher than current levels.
Water levels on the Red River in Selkirk at PTH 4 increased 0.1 ft. since yesterday to 721.68 ft.
Assiniboine River
Water levels on the Shellmouth Reservoir increased by 1.18 ft. since yesterday to 1,411.55 ft. Inflows into the Shellmouth Reservoir have decreased to approximately 16,500 cfs. Outflows are the maximum possible with current reservoir levels at 9,080 cfs.
The Shellmouth Reservoir is forecast to receive significant run-off from the current storm, adding to current high water levels. The dam will be operated to prevent outflows from exceeding 10,000 cfs.
Water levels on the Assiniboine River near the Sioux Valley First Nation are 1,202.57 ft. Works on the dikes will bring flood protection level to 1,207 ft., well above the forecast peak water elevation.
Water levels on the Assiniboine River at the First Street Bridge in Brandon are 1,178.72 ft., increasing 0.5 ft. since yesterday. Water levels at Brandon will continue to increase as they approach the prolonged crest, which is forecast to occur between May 12 to 14. The lower range of the forecast peak at the First Street Bridge in Brandon is 1,179.8 ft., 0.3 ft. higher than the 1976 flood of record. Flood protection dikes in the area are still well above the forecast peak.
Flows in the Portage Diversion channel this morning are at 20,500 cfs. Inflows upstream of Portage la Prairie are 36,500 cfs. Flows on the Assiniboine River downstream of the diversion are approximately 16,000 cfs. Flows on the Assiniboine River downstream of the diversion will gradually increase in the next few days.
Souris River
The Souris River is now declining at all reaches, however, the precipitation from the current storm may increase flows. Despite this anticipated increase from the storm, the Souris River is expected to remain below recent peak levels.
Precipitation from this unstable weather event may result in localized overland flooding on adjacent tributaries and streams in the area.
Other Major Waterways
It is anticipated that water levels on Manitoba’s major lakes will be very high this year. Manitoba Water Stewardship will be monitoring conditions closely and will provide warnings when necessary.
Lake Manitoba water levels have risen to 813.78 ft., increasing 0.04 ft. since yesterday. Water levels on Lake Manitoba and Lake St. Martin may be wind-affected. Outflows from Lake Manitoba were recorded at 12,400 cfs late yesterday. The Fairford Dam, at the outlet of Lake Manitoba, is operating at full capacity.
Water levels on Lake Winnipeg at Gimli are 715.33 ft., increasing slightly since yesterday.
For more information, see www.manitoba.ca/flooding. The most up-to-date highway information is at www.gov.mb.ca/mit/roadinfo or 1-877-MBRoads (1-877-627-6237) and on Twitter by following @MBGov.
