Manitoba’s flood forecast levels have been increased significantly this spring due to three major storms that produced record rain on already saturated land across southern Manitoba. Precipitation amounts are almost 300 per cent of normal in the Souris River basin. Other areas of southern Manitoba have experienced rain amounts between 150 and 250 per cent of normal.
Storms and high water flows from other provinces and states have contributed to a flood of record that will continue this summer and into the fall.
Rain can have a significant and quick impact on river and lake levels when soils are saturated and waterways are already at high levels. Forecasts will be adjusted on an ongoing basis and weather will play a role in increasing water levels around the province. Flood-protection systems will continue to be maintained and monitored.
Near gale-force winds are forecast for lakes Manitoba and Winnipeg for the next 12 hours before they start to diminish.
About 19 federal and provincial volunteers are providing assistance in Lundar today. Approximately 20 Manitoba Conservation forest-fire crews are assisting in The Pas and approximately 30 are in the RM of Ochre River.
Work to reinforce and construct dikes at Ralls Island in The Pas is underway. Additional protection is required as a result of Saskatchewan flood forecasts for the Saskatchewan River.
Across Manitoba, there are currently 2,121 Manitobans evacuated from their homes.
The STARS helicopter is temporarily unavailable for approximately 10 days. Land-based and other air-ambulance services and paramedic services are available and able to respond across the province. Road closures and conditions are being carefully monitored to help ambulances navigate and reach all areas of the province. STARS is a charitable, non-profit organization that has responded to more than 20,000 emergencies since it began in 1985. The service responds to critically injured and ill patients, with approximately half of its missions being inter-hospital while the other half are on-scene calls such as on highways, in remote areas and industry work sites.
The scale, scope and ongoing nature of this year’s flood can be very challenging for affected Manitoba families. There are resources to help deal with stress and anxiety which result from a crisis situation such as this flood. Resources include Manitoba Farm and Rural Support Services 1-866-367-3276 (1-866-FOR-FARM) toll-free; Klinic Community Health Centre 24-hour Crisis Line 786-8686 in Winnipeg or 1-888-322-3019 toll-free; and Health Links-Info Santé which can also help find resources through local regional health authorities or community mental-health services offices at 788-8200 in Winnipeg or 1-888-315-9257 toll-free. Additional information and tips are available at www.gov.mb.ca/flooding/stressinfo.html.
Flood Forecast
Environment Canada has issued a strong wind warning for Lake Manitoba and all of Lake Winnipeg. Municipalities and residents are advised to prepare for wind-affected lake levels and significant wave uprush along the shoreline of the lakes.
Wind set-up alerts for today include:
• A severe wind set-up alert has been issued for the west shore of Lake Winnipeg’s South Basin and the west shore of Lake Winnipeg’s Traverse Bay. This includes communities such as Traverse Bay, Victoria Beach, Gimli, Winnipeg Beach, Dunnottar, Matlock and Chalet Beach.
• A high wind set-up alert has been issued for Lake Manitoba’s west and south shore. This includes communities such as Sandy Bay, Lynch’s Point, Twin Lakes Beach and Delta Beach.
• A moderate wind-set up alert has been issued for Lake Winnipegosis’ south shore, Dauphin Lake’s south shore, the east shore of Lake Manitoba’s South Basin, the east shore of Lake Winnipeg’s South Basin and the east shore of Traverse Bay. This includes communities such as Winnipegosis, Ochre and Delta Beach, and Lundar Beach.
The amount of precipitation that has fallen in May this year in Manitoba is very significant. A map showing normal rain amounts for May can be found online. The following lists how much more rain the area has received compared to normal amounts for May.
• Souris, Estevan, Sask. and Minot, N.D., have received 297 per cent of normal precipitation.
• Hamiota has received 294 per cent of normal precipitation.
• Pierson has received 279 per cent of normal precipitation.
• Ste. Rose du Lac has received 254 per cent of normal precipitation.
• Virden has received 250 per cent of normal precipitation.
• McCreary has received 246 per cent of normal precipitation.
• Melita has received 229 per cent of normal precipitation.
• Dauphin and Arborg have received 195 per cent of normal precipitation.
• Brandon has received 190 per cent of normal precipitation.
• Portage la Prairie has received 182 per cent of normal precipitation.
Much of this rain occurred during three major storm events May 6 to 10, May 21 and 22 and May 27 to 31. More rain is forecast for today across much of southern Manitoba. Soils are very saturated and most rain will run-off or collect in local depressions.
Prior to this precipitation, flood potential was high across much of southern Manitoba due to very high soil-moisture conditions, above normal snow-water content in snowpack and above-normal snowpack depth. Early forecasts were based on these above-mentioned conditions and included a range which accounted for unfavourable weather conditions. Precipitation experienced in May is outside the bounds of what is typically classified as unfavourable weather which required revising forecasts to capture these extraordinary precipitation amounts.
• As a result, Lake Manitoba’s forecast was updated following each significant precipitation event.
• Lake forecasts were updated for many lakes to account for these extraordinary conditions.
The peak natural flow of the Assiniboine River at Holland/Portage la Prairie of 58,500 cubic feet per second (cfs) is a one-in-350-year rate.
The volume of water that has flowed through the Assiniboine River near Holland in April and May is 3,900,000 acre-feet. This quantity of water is over 20 per cent greater than the record flood volume in 1976 which reached 3,200,000 acre-feet. The forecast volume of water predicted to pass through the Assiniboine River between April and the end of June is 5,400,000 acre-feet, which will be about 50 per cent greater than the highest volume recorded since record keeping began.
Many Manitoba lakes are experiencing extraordinary flooding events due to 2010 fall precipitation, spring soil moisture conditions, snowpack, these precipitation events and the resultant high run-off flows.
Forecast peak flows for the Souris River are as follows:
• In Melita, with average weather conditions, water levels are forecast to reach 1,411.2 feet and under unfavourable weather conditions could reach 1,412.0 ft. between June 16 and 22. The upper range of the forecast crest is 0.34 ft. above the previous crest on April 22.
• Water levels in Souris are cresting at 1,360.05 ft. This level is 0.19 ft. above the previous crest on April 23.
• In Wawanesa, with average weather conditions, water levels could reach 1,158.3 ft. and under unfavourable conditions are forecast to reach 1,159.3 ft. between June 7 and 11. This forecast crest is due to recent heavy rains. The upper range of this forecast is 1.33 ft. above the previous crest reached on April 26.
Water levels on the Saskatchewan River near The Pas are expected to reach 855.5 to 857 ft., depending on the weather. The reinforcement of existing dikes and the building of permanent dikes are underway.
Lake levels are attached.
Assiniboine River
Water levels on the Qu’Appelle River at Welby are 16.54 ft. today, increasing 0.04 ft. since yesterday.
Water levels on the Shellmouth Reservoir are 1,408.65 ft., decreasing 0.30 ft. since yesterday. Inflow into the Shellmouth Reservoir is 3,060 cfs and outflow is 5,275 cfs today.
Water levels on the Assiniboine River at the First Street Bridge in Brandon have crested at 1,179.85 ft., decreasing 0.02 ft. from the most recent crest of 1,180.12 ft. on June 6. Flows at the First Street Bridge are estimated to be 26,400 cfs.
Inflow upstream of Portage la Prairie is 46,980 cfs. Flows in the Portage Diversion channel are 28,900 cfs. Flows on the Assiniboine River at the Portage Reservoir control gates are 18,080 cfs. Inflow into the Portage Reservoir is forecast to reach between 47,000 and 48,000 cfs by June 8 to 10.
Water levels in the Baie St. Paul area are 799.93 ft., a decrease of 0.04 ft. since yesterday.
Souris River
Plum Creek decreased 0.66 ft. since yesterday to 1,376.36 ft.
Water levels on the Souris River increased since yesterday to 1,411.16 ft. at Melita, 1,360.04 ft. at Souris and 1,158.06 ft. at Wawanesa. Flows on Souris River at Wawanesa are estimated to be almost 18,700 cfs today.
Other Waterways
Water levels on the Saskatchewan River at Ralls Island are 853.33 ft., an increase of 0.07 ft. with a flow of 62,300 cfs.
The estimated outflow from the Fairford River water control structure is 18,600 cfs today. The structure continues to operate at full capacity due to the high level of Lake Manitoba.
