Record precipitation over the past two months has been observed in all sub-watershed regions except for Lac La Croix and Rainy-Namakan, where 2014 was slightly greater. The inflows to these lakes, however, have been much higher in 2022 due to the later snowmelt in April and continued above-normal precipitation almost every week for the past two months.
This precipitation has led to the development of record flows in most areas of the entire Winnipeg River drainage basin in Ontario, Manitoba and Minnesota. In addition to damages such as road and bridge washouts in many areas, damage to shorelines and shoreline structures is occurring across the region on both small and large rivers and lakes. Many communities have declared states of emergency with homes, businesses, and community infrastructure such as sewage treatment plants at risk. This is a full regional flooding event that is without precedent on record, and beyond the capacity of any dams in the system to manage. Many water level gauges across the region have reported new records for lake and river water levels and river flows.
Total inflow from April 1-May 31 set a new record for all of the major lakes in the Winnipeg River drainage basin (Namakan Lake, Rainy Lake, Lake of the Woods and Lac Seul).
Rainfall over the past several days once again saw a rise in tributary flows in many areas.
This added water will further delay a return to normal water levels, which could be many weeks out for most areas of the watershed.
The current level of Lake of the Woods is 323.89 m (1062.6 ft), over 95th percentile level for this time of year. The average lake level rose by 10 cm (4 in) over past week. The lake level has risen above the 2014 peak of 323.78 m (1062.29 ft) and is below the record peak since regulation began of 324.31 m (1064.0 ft), set in July of 1950.
The level of Lake of the Woods is expected to rise by approximately 9-12 cm (4-5 in) over the next 7 days, the rate depending on the rainfall received across the region. With drier weather the rate of rise should slow, but timing of the peak will depend on rainfall this month. Lake of the Woods water levels will likely remain above the Legislated Operating Range for many weeks. Record lake levels are possible and will depend on rainfall across the watershed in the next couple of weeks.
As the lake continues to rise, the outflow from the lake will very gradually rise. This should result in the level of the Winnipeg River between Kenora and Minaki also gradually rising, with any local precipitation adding temporarily to levels in this stretch of the river. The level rise over the next 7 days below Norman Dam and down to Minaki is expected to be 2-4 cm (1-2 in).
The current level of Lac Seul is 356.64 m (1170.1 ft), over 95th percentile level for this time of year. Lac Seul inflow is very high, resulting in a rise of 17 cm (7 in) over the past week. The lake is nearing the Flood Reserve, a range of water levels above the normal operating range defined by federal Order-in-Council that corresponds to a key level for dam safety concern for the Ear Falls dam. Lac Seul authorized outflow is 800 m³/s with no changes currently scheduled. The outflow has risen in recent days with lake level rise, but will be reduced to 800 m³/s on June 2.
The main body of Lac Seul is expected to rise by 11-14 cm (4-6 in) over the next 7 days with the rate of rise slowing if drier weather lasts through the forecast period.