Province of Manitoba » Water Stewardship » Water Information » Flood Forecasting Reports » Lake Manitoba & Lake St. Martin Forecast - September 20, 2005

 

The forecast for Lake Manitoba and Lake St. Martin has been updated. The result is summarized below and in the TABLE & CHART. 

• The September 20, 2005 level of 812.55 feet for Lake Manitoba is 0.85 feet higher than the average September level for the past 30 years.
• Lake St. Martin is at 801.4 feet, which is 3.4 feet above the average September level for the past 30 years.
• The level of Lake Manitoba and Lake St. Martin is expected to decline quite significantly this autumn as shown on the attached table and graph. This is due to evaporation far exceeding precipitation during the autumn months. The high outflows will also contribute to the decline of Lake Manitoba.
• Lake level forecasts are based on no changes in gate settings at Fairford Dam. Flows at the Dam will gradually decrease as shown, due to the decline in Lake Manitoba levels.
• While the level of Lake St. Martin is much above average, it is below flood stage and declining. The lake is not large enough to be subject to a great wind set-up, and therefore storm related flooding this autumn is unlikely.
• Shoreline erosion may occur on Lake Manitoba this autumn if strong winds develop, especially with the somewhat above average levels. Flooding of shoreline properties due to wind set-up and wave uprush is unlikely but not impossible if extreme winds develop.