As a result of the weekend precipitation, some Assiniboine River tributaries will have minor increases but will stay below water levels reached in previous crests. The storm is not expected to cause significant water level rises on the Assiniboine River.
Along the Red River, water levels increased in tributary streams throughout the basin. The main stem of the Red River may experience a more prolonged crest and slower recession, but not an increase in peak water levels.
In the Souris River basin, the storm could result in localized overland flooding in the area.
In the Dauphin Lake Basin, some streams affected by high-elevation snowfall will see another peak, with water levels expected to stay within stream banks, depending on how fast the snow melts.
Water levels just upstream of the floodway inlet are 764.08 ft., with flows of 76,000 cfs. Flows in the floodway are approximately 36,800 cfs. Flows above the floodway inlet will slowly increase until the peak occurs between May 2 to 5. Water is now moving through the west notch of the floodway’s east embankment, which was lowered in 2009 to improve the movement of water into the floodway.
Water levels on the Assiniboine River at the First Street Bridge in Brandon are 1,178.9 ft., increasing 0.18 ft. since yesterday. Water levels at Brandon will continue to increase as they approach the prolonged crest, with the forecast peak to occur between May 11 to 13. Water levels in Brandon are now the second highest in recorded history, surpassed by 1923 peak water levels. Flood protection dikes in the area are at 1,184 ft., well above the upper range of the forecasted peak at 1,181.2 ft.
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 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.
Overland flooding is expected in areas that received significant precipitation.
Flood Response
The storm brought considerable precipitation to southern Manitoba in the form of both rain and snow in the last 24 hours. The Parklands area received the greatest amount of snowfall with 25 centimetres of snow reported throughout the region and up to 50 cm accumulating in localized, high-elevation areas.
Flood-protection systems held across the province despite precipitation and extreme winds that caused waves as high as two feet along some of the community ring dikes in the Red River Valley. The dikes will continue to experience high and ongoing flows for several weeks.
There has been a precautionary evacuation of four homes in St-Lazare outside of the community ring dike, due to loss of road access (water over the road) near the junction of PTH 42 and PTH 41. Local officials are meeting with nine other homeowners who may also be affected.
Work to reinforce dikes along the Assiniboine River in the RMs of Cartier, St. Francois Xavier and Headingley is continuing.
Work on the dikes at Sioux Valley will bring the flood protection level to 1,207 feet, well above the forecast peak.
There are 1,879 people evacuated from their homes, mostly because of a lack of road access. Approximately 38 people returned home to the Roseau River First Nation.
Approximately 74 homes across Manitoba have been affected by flood waters, mostly due to basement seepage. A more thorough assessment will be done after the flood.
There are 59 provincial roads closed and 27 roads with a caution advisory. There are about 650 municipal roads closed. Drivers are reminded to exercise caution when driving, stay off closed or flooded roads and be prepared to use alternative routes.
Red River
The Red River is near crest in St. Adolphe today, increasing 0.12 ft. since yesterday. Sustained high flows are expected for a prolonged period along all reaches of the river.
Water levels on the Red River at Morris have declined 0.2 ft. since yesterday to 779.1 ft. Water levels at many points along the Red River fluctuated due to high winds, with water levels increasing as much as one ft. and decreasing over 1.5 ft.
Water levels at James Avenue in Winnipeg increased 0.18 ft. since yesterday to 19.01 ft. Flows at James Avenue this morning were approximately 55,700 cfs. Without the flood-protection works in place across the province, water levels at James Avenue would have been 30.7 ft. or approximately 11.7 ft. higher than current levels. Current flows without flood protection would be 111,000 cfs, which is higher than peak flows recorded at James Avenue in 1950, 1979 and 1996.
Water levels on the Red River in Selkirk at PTH 4 increased 0.73 ft. since yesterday to 722.41 ft.
Assiniboine River
Water levels on the Shellmouth Reservoir have increased by 0.46 ft. since yesterday to 1,412.01 ft. Inflow into the Shellmouth Reservoir has decreased to approximately 13,000 cfs. Outflows are the maximum possible (10,000 cfs) at this water elevation.
Flows in the Portage Diversion channel this morning are at 21,300 cfs. Inflow upstream of Portage la Prairie is 37,300 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 to 17,000 cfs today.
Souris River
The Souris River is now declining at all reaches, however, the precipitation from the recent storm in the Melita-Brandon area may increase flows somewhat in the river. Despite the anticipated increase from the storm, any new crest for the Souris River is expected to be below recent peak levels.
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 are 813.86 ft., increasing 0.04 ft. since yesterday. Water levels on lakes may be affected by wind today. Outflows from Lake Manitoba were recorded at 11,500 cfs late yesterday. The Fairford Dam at the outlet of Lake Manitoba is operating at full capacity.
Lakes across Manitoba, such as Lake Manitoba, Shoal Lakes, Lake St. Martin, Oak, Pelican, Rock and Dauphin lakes can expect high winds today with potential for wind gusts of up to 40 to 70 km/h. Those properties exposed to north or northwest winds may experience ice movement and pileup. The risk of shoreline ice pileup is high on Lake Winnipeg (south basin), Lake Manitoba, Pelican Lake and North, East and West Shoal Lakes. It is medium on Lake Winnipegosis, Lake St. Martin, Oak, Rock and Red Deer lakes.
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.
