Manitoba Water Stewardship’s Hydrologic Forecast centre reports the flood forecast for the Red River Valley in southern Manitoba remains somewhat uncertain due to a storm system expected to affect the watershed over the next three days. However, indications are a flood of a 1979 magnitude is likely along the Red in Manitoba. The crest is expected at Emerson from April 5 to 10 and at Winnipeg from April 12 to 17.
The first part of the current storm produced 40 to 65 millimetres (1.6 to 2.6 inches) of rain over portions of western Manitoba from Souris to Dauphin yesterday but produced only five to 10 mm (0.2 to 0.4 in.) over the Red River Valley in southern Manitoba. The North Dakota portion of the Red River watershed received five to 10 mm (0.2 to 0.4 in.) and some areas in the Minnesota portion received 40 mm (1.6 in.). This first part of the storm produced less rain over the Red River basin than expected.
The next portion of the storm, expected to move slowly northward over Minnesota in the next few days, is expected to produce 25 to 50 mm (one to two in.) of rain from Grand Forks to Winnipeg and 20 to 30 mm (0.8 to 1.2 in.) from Wahpeton to Grand Forks. Colder weather with sub-zero temperatures and snow is expected to develop in southern Manitoba by Wednesday. This will last until the end of the week and is expected to slow down run-off as water becomes frozen in fields.
The chance of a 1997-magnitude flood in the Manitoba portion is still about 10 per cent. This has not changed from the previous flood outlook as the unfavourable weather scenario for that outlook had assumed the heavy precipitation now forecast. Anticipated peak stages in the Manitoba portion are somewhat less relative to 1997 than at U.S. points due to lower run-off potential on Manitoba tributaries.
Peak stage forecasts for the Red River will now be updated daily. Forecasts will become more reliable as additional information becomes available on actual run-off and weather conditions.
The heavy precipitation in western Manitoba yesterday increased the potential for flooding on the Assiniboine and Souris rivers and in the Westman region. Some localized overland flooding has already been reported. This will subside during the next few days due to colder weather, but is predicted to start again when the weather warms next weekend.
Additional heavy precipitation is expected over the Souris and Pembina river watersheds during the next few days, further increasing the flood potential in these areas. Specific updated forecasts for rivers in western Manitoba will be provided later this week in conjunction with daily reports and flood sheets.
The latest outlooks and reports can be found online.
Flood Liaison Offices:
Tomorrow, two flood liaison offices will open to provide information to residents of the Red River Valley. Flood liaison officers will provide flood-related information to residents including details on existing flood-protection levels, current forecasted flood levels and the status of community ring dike closures. For information on obtaining sand-bagging materials, residents are asked to contact their rural municipality.
The provincial flood liaison offices will be open every day from 7 a.m. to 9 p.m. until the current flood risk is over. The offices are at 871 Southwood Rd, in Morris, 204-746-7325, and 200 Saulteaux Crescent in Winnipeg, 204-945-2354.
Red River Valley Preparations:
• Local communities in the Red River Valley, the Manitoba Emergency Measures Organization and Manitoba Water Stewardship are finalizing plans for flood response.
• Two full closures of ring dikes are anticipated at Riverside (approximately 55 people) and Roseau River (approximately 800 people.) Evacuation plans are being considered and finalized for these communities, if required. Planning would be co-ordinated through the RM of Morris for Riverside and the Manitoba Association of Native Fire Fighters for the community of Roseau River.
• To date, 11 communities have been identified for potential partial ring dike closures during the flood period. With partial ring dike closures, full community evacuations are not anticipated. It is currently anticipated that there will be alternative routes in and out of these communities. They are Aubigny, Brunkild, Dominion City, Emerson, Gretna, Letellier, Morris, Rosenort, St. Adolphe, Ste. Agathe, and St. Jean Baptiste.
• Planning is underway for limiting travel or closing certain highways and provincial roads as water levels rise. Of particular note, parts of PTH 75 are expected to be limited to traffic and then closed in the coming weeks.
Motorists are reminded to:
• Respect road barriers that are set up to manage traffic flow safely.
• Water levels can change rapidly – roads will have barriers only if there is potential risk to motorists.
• Driving on a closed road is a risk to individuals and to emergency personnel who may have to respond to any incidents.
