A storm with high winds is expected to bring snow into the Brandon area, which is under a winter storm watch. In the Red River basin, 20 to 30 millimetres of rain and strong winds are expected. Between 35 and 45 mm of rain today and tomorrow in the Melita area may result in overland flooding.
Due to high wind gusts forecast across Manitoba tomorrow, properties with flood-protection works that are exposed to north winds can expect wind setup and wave action, and are advised to assess the need for additional flood-protection reinforcements.
Lakes across Manitoba including Lake Manitoba, Shoal Lakes, Lake St. Martin, Oak, Pelican, Rock and Dauphin lakes can expect high winds tomorrow with potential for wind gusts up to 40 to 70 km/h. Those properties exposed to north winds may experience ice movement and pileup. Due to this wind and the deteriorated ice on many lakes, the risk of shoreline ice pileup has increased for most lakes in southern Manitoba.
Over the next three days, flows along the Assiniboine River east of the Portage Diversion will be gradually increased from 15,000 cubic feet per second (cfs) to 18,000 cfs. Manitoba Water Stewardship, the Manitoba Emergency Measures Organization and Manitoba Infrastructure and Transportation will meet with the three municipalities along this portion of the river today. The meeting will focus on plans for the increased flows. These communities were previously advised to raise protective dikes to 1976 levels.
The coinciding crest of the Red and the Assiniboine rivers will not occur tomorrow, but on May 4, due to increased flows on the Assiniboine River. The crest at James Avenue is expected to be around 20 ft.
Flood Response
PTH 75 between Morris and St. Jean Baptiste is expected to remain closed until mid-May following an assessment of flood projections. This exact opening time following cleanup of the highway will depend on the weather.
The CP rail line at Emerson will be reopened later today.
The natural Red River flow at Winnipeg for the 2011 flood on the Red River as measured at James Avenue is now larger than those recorded in the floods of 1950, 1979 and 1996.
Additional flood protection work will occur at the Sioux Valley First Nation near Brandon to add an additional two feet of protection on the dikes in the community as a result of increased flows coming from the Shellmouth Dam.
PTH 5 near the Spruce Woods Provincial Park between Carberry and Glenboro will remain closed for the next four to six weeks due to flooding and continued high water levels. The lower campground has been affected by flooding, however, it will take some time to assess and repair damages once waters recede.
The total number of evacuations stands at 1,916 people, mostly due to loss of safe road access.
The Canada Revenue Agency (CRA) has advised that taxpayers can access the CRA’s taxpayer relief provisions at their website at www.cra-arc.gc.ca or by calling toll-free 1-800-959-8281.
Flood Forecast
Flood warnings have been issued 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 the Plum Creek to the Souris River (including the town of Souris).
Flood watches are in place for the Assiniboine River downstream of Portage la Prairie and the Qu’Appelle River in the St-Lazare area.
Red River
The upper range of the forecast peak for the Red River is below 2009 levels for all points on the river. The Red and Assiniboine river forecasts will be updated after the unstable weather system.
The Red River is cresting in Morris today. Sustained high flows are expected for a prolonged period along all reaches of the river.
Water levels just upstream of the floodway inlet are 763.65 feet, with flows of 75,600 cfs. Flows in the floodway are approximately 33,900 cfs. Flows above the floodway inlet will steadily increase until the peak occurs on or around May 1.
Without Manitoba’s flood protection works, water levels at James Avenue would have been 30.3 ft., or approximately 11 ft. higher than current levels. The natural flows at James Avenue today would have reached 109,000 cfs.
Water levels at James Avenue in Winnipeg have increased 0.24 ft. since yesterday to 19.04 ft. Flows at James Avenue this morning were approximately 55,600 cfs. Flows on the Assiniboine River will be increasing in the upcoming days.
Water levels on the Red River at the Selkirk PTH 4 increased 0.22 ft. since yesterday to 721.58 ft.
Assiniboine River
Water levels on the Shellmouth Reservoir have increased by 1.12 ft. since yesterday to 1,410.21 ft. Inflow into the Shellmouth Reservoir has decreased to approximately 14,300 cfs. Outflows are the maximum possible with current reservoir levels of 6,910 cfs.
The Shellmouth Reservoir is forecast to receive near record volumes of water from upstream waterways this spring and will be contributing high flows to the Assiniboine River, prolonging the crest period for as much as three to four weeks. The dam will be operated to prevent outflows from exceeding 10,000 cfs.
Water levels on the Assiniboine River at the First Street Bridge in Brandon are 1,178.22 ft., increasing 0.47 ft. since yesterday. Water levels at Brandon will continue to increase as the crest approaches around May 12 to 14. The upper range of the forecast peak at the First Street Bridge in Brandon is 1,181.2 ft, 1.66 ft. higher than 1976. Flood protection dikes in the area are still well above the forecast peak.
Flows in the Portage Diversion channel this morning are at 21,500 cfs. Inflow upstream of Portage la Prairie is 36,500 cfs. Flows on the Assiniboine River downstream of the diversion are approximately 15,000 cfs. Flows downstream of the diversion will increase to 18,000 cfs in the next few days.
Souris River
The Souris River is now declining at all reaches. However, the storm forecast for the Melita-Brandon area may increase flows somewhat in the river. The new crest for the Souris River will be below the recent crest.
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 providing warnings when necessary.
Lake Manitoba water levels have risen to 813.76 ft, increasing 0.06 ft. since yesterday. Outflows from Lake Manitoba were recorded at 12,300 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 715.24 ft., decreasing slightly since yesterday.
Tomorrow the risk for ice pileup is high on Lake Winnipeg (south basin), Lake Manitoba and on the North, East and West Shoal lakes; medium for Dauphin Lake, Lake Winnipegosis, Lake St. Martin, Oak, Pelican and Rock lakes; and it is low for Red Deer Lake.
The flood watch for the Saskatchewan River near Ralls Island and the Carrot River at all reaches within Manitoba has been cancelled.
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.
