Secretariat

Last week’s forecasts from various weather agencies overestimated precipitation over the past weekend. For headwater areas to Lake of the Woods, including La la Croix and Seine River, the smaller rainfall totals have allowed for high river levels to peak and start receding.

These high flows have led operators at dams at Rainy Lake and Namakan Lake to ramp up outflow to high spring levels in compliance with directives from the International Joint Commission’s Water Levels Committee. The Lake of the Woods Control Board has no authority over these flows, but is in close communication with this committee and is adjusting outflow from Lake of the Woods proactively in response to upstream conditions. Lake of the Woods outflow was increased from 475 to 550 m³/s on Tuesday, May 19. No further flow changes are currently scheduled. Should wet weather return, further increases are possible.

The current level of Lake of the Woods is 322.79 m (1059.0 ft), the median or 50th percentile level for this time of year. The average lake level rose by 6 cm (about 2.5 in) over the past week, and is expected to rise by 4-6 cm (about 2-2.5 in) over the next week. The level of the Winnipeg River between Kenora and Whitedog is not expected to change over the next week.

At Lac Seul, inflows from Lake St. Joseph continue to rise with the tail end of snowmelt happening in that basin. Very high flows from tributary rivers to Lac Seul near Sioux Lookout, the English River and the Sturgeon River, have peaked and should begin to drop with the drier forecast. Inflow to Lac Seul will remain seasonally high this month, regardless of additional rain amounts.

The current level of Lac Seul is 355.47 m, 1166.2 ft, which is 60th percentile for this time of year. The lake level increased by 20 cm (8 in) over the past week and is expected to rise by a similar amount over the next week. Lac Seul authorized outflow will be increased from 350 to 400 m³/s on Thursday May 21.

A number of website visitors have reported issues accessing up-to-date graphs and reports on the Basin Data page using Android devices. To address this issue, the Secretariat has updated links to these graphs and reports. All links to products as listed on the Basin Data page are correct, but those accessing individual graphs and reports using bookmarks will need to update their bookmarks to open the latest graphs going forward.

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Dry conditions over the past week have helped ease flows in the Winnipeg River basin, particularly in the headwaters where tributary flows remain well above normal for this time of year. The dry and warm weather is expected to persist until Sunday, after which a shift in the weather pattern is forecast. A low pressure system will move across the region on Monday, bringing significant moisture in the form of widespread precipitation and embedded thunderstorms. Although the exact track of the system is still uncertain, the rain is expected to linger for a couple days and be heavy at times.

This precipitation will halt the declining flows and cause inflows to the major lakes to increase over the coming week. Although both Lake of the Woods and Lac Seul are still refilling, continued gradual outflow increases are required to slow the rate of lake level rise. The LWCB is monitoring conditions closely and using the adopted Regulation Strategy to guide operations in consideration of the various interests across the basin.

The current level of Lake of the Woods is 322.73 m (1058.8 ft), a 50^th percentile level, within the normal range for this time of year. The average lake level increased by 7 cm (2.8 in) over the past week and is expected to increase by 8 to 15 cm (3 to 6 in) over the next week. Lake of the Woods authorized outflow will increase to:

• 475 m³/s on Friday, May 15^th
• 550 m³/s on Tuesday, May 19^th

Each of these flow increases will cause the level of the Winnipeg River to increase, with a total level rise of approximately 32 cm (13 in) directly downstream of the Norman Dam and 17 cm (7 in) above the Dalles. The level at Minaki will not be affected by this flow change.

The current level of Lac Seul is 355.26 m (1165.5 ft), a 60^th percentile level, within the normal range for this time of year. The lake level increased by 23 cm (9 in) over the last week and is expected to increase by 18 to 25 cm (7 to 10 in) over the next week. Lac Seul authorized outflow will increase to:

• 300 m³/s on Friday, May 15^th
• 350 m³/s on Tuesday, May 19^th

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The LWCB Basin Data page will not be updated on Monday, May 18^th (Victoria Day in Canada). Daily data updates and publication will resume on Tuesday, May 19^th.

Lac Seul is refilling quickly and to manage level rise while inflow to the lake continues to climb, an outflow increase to 250 m³/s is scheduled for Tuesday, May 12^th.

Flows in the eastern headwaters of the basin continue to rise and are now well above normal for early May. Dry weather over the past few days has provided some relief, and water levels in the upper tributaries are expected to peak over the weekend. As this large volume of water moves through the system, inflows to the major downstream lakes continue to increase.

At Lac Seul, refill is progressing rapidly, with lake levels now within the normal range. At Lake of the Woods, inflows are expected to rise gradually throughout the week. While local inflows are declining due to dry conditions, operators at Rainy Lake are making significant outflow increases to pass water arriving from the headwaters. To manage Lake of the Woods level rise, additional staggered outflow increases are required.

The current level of Lake of the Woods is 322.66 m (1058.6 ft), a 45^th percentile level, within the normal range for this time of year. The average lake level increased by 6.5 cm (2.6 in) over the past week and is expected to increase by 4 to 5 cm (1.5 to 2 in) over the next week. Lake of the Woods authorized outflow will increase to:

• 325 m³/s on Friday, May 8^th
• 375 m³/s on Sunday, May 10^th
• 425 m³/s on Tuesday, May 12^th

Each of these flow increases will cause the level of the Winnipeg River to increase, with a total level rise of approximately 33 cm (13 in) directly downstream of the Norman Dam and 15 cm (6 in) above the Dalles. The level at Minaki will not be affected by this flow change.

The current level of Lac Seul is 355.03 m (1164.8 ft), a 50^th percentile level, within the normal range for this time of year. The lake level increased 25 cm (10 in) over the last week and is expected to increase by 18 to 22 cm (7 to 8.5 in) over the next week. Lac Seul authorized outflow is 175 m³/s. An update on the next outflow increase will be provided early next week.

The spring freshet is in full swing across the Winnipeg River basin. Areas to the east, which saw exceptionally high rainfall at the end of April, continue to see rising flows in tributary rivers and inflows to major lakes.

In the Lac Seul sub-basin, flows have risen sharply to high seasonal levels in the east of the basin, including into Lake St. Joseph and in the natural tributaries to Lac Seul east of Sioux Lookout (Sturgeon River, English River). Lac Seul level is projected to rise above the minimum fisheries target for May 15 with this strong freshet response.

Lac Seul authorized outflow will be increased from 100 to 175 m³/s on Tuesday, May 5.

In the Lake of the Woods sub-basin, rainfall at the end of April was heaviest in the eastern headwater regions in Minnesota and Ontario. Flows measured in the major tributaries from these headwaters (Namakan River at the outlet of Lac la Croix and Seine River, respectively), are exceptionally high for early May. Flows in Turtle River in Ontario, another important tributary draining the north of the Rainy basin into Rainy Lake is moderately high. Dam operators at Namakan Lake and Rainy Lake are increasing outflows as this water makes it way through the system, which will result in rising inflows to Lake of the Woods over the next week.

In keeping with the LWCB’s adopted spring Regulation Strategy, Lake of the Woods authorized outflow will be increased from 225 to 275 m³/s on Tuesday, May 5 and from 275 m³/s to 325 m³/s on Friday, May 8. The Winnipeg River level below Norman Dam is expected to rise by 10 cm (4 inches) following each of these outflow increases. The Winnipeg River level at Minaki will not be affected by these flow changes.

2026.04.30 Level Forecast

Above‑normal precipitation concentrated on the eastern side of the Winnipeg River Basin occurred over the past seven days. Tributary flows and lake inflows in the Upper English River and the headwaters of the Rainy-Namakan basins have increased in response to this precipitation. Lac Seul refill has begun, and the level is rising rapidly with snowmelt. For Lake of the Woods, inflows have remained relatively stable, and the lake level continues to rise. Current forecasts indicate dry conditions over the coming week; however, Lake of the Woods inflows could rise as upstream basins respond to the recent precipitation. Basin conditions will be closely monitored to assess whether outflow adjustments may be necessary if higher‑than‑anticipated precipitation develops.

The current level of Lake of the Woods is 322.59 m (1058.4 ft), a 40^th percentile level, within the normal range for this time of year. The average lake level increased by 5.5 cm (2.2 in) over the past week and is expected to increase by 5 to 6.5 cm (2 to 2.6 in) over the next week. Lake of the Woods authorized outflow is 225 m³/s, with no changes scheduled at this time.

The current level of Lac Seul is 354.78 m (1164.0 ft), a 25^th percentile level, within the normal range for this time of year. The lake level increased 17 cm (6.7 in) over the last week and is expected to increase by 23 to 26 cm (9 to 10.2 in) over the next week. Lac Seul authorized outflow is 100 m³/s, with no changes scheduled.

Although the level of Lac Seul has started rising with the rain and melting snow over the weekend, forecasts indicate a return to dry conditions over the next week. Therefore, in order to capture as much of the spring inflow as possible, Lac Seul outflow will be reduced to 100 m³/s on Tuesday, April 28^th. This will allow the lake to continue refilling should dry conditions persist into May.

With warm temperatures across the Winnipeg River basin and rainfall forecast for tomorrow, river flows and lake inflows are expected to increase. At Lac Seul, this will mark the beginning of the refill period, with lake levels rising rapidly as the snowpack melts. At Lake of the Woods, small, incremental increases to outflow will begin tomorrow and are likely to continue into next week, as upstream basin inflows are expected to increase. The lake level has been rising steadily, and with ice cover still in place, outflow adjustments are necessary to slow the rise and reduce the risk of damage to docks fixed in the ice.

The current level of Lake of the Woods is 322.54 m (1058.2 ft), a 40^th percentile level, within the normal range for this time of year. The average lake level increased by 5 cm (2 in) over the past week and is expected to increase by 6 to 10 cm (2.4 to 4 in) over the next week. Lake of the Woods authorized outflow will increase to 225 m³/s on Friday, April 24^th. Additional small outflow increases may be required next week.

This flow increase will cause the level of the Winnipeg River to increase by approximately 4.5 cm (1.8 in) directly downstream of the Norman Dam and by 1.5 cm (0.6 in) above the Dalles. The level at Minaki will not be affected by this flow change.

The current level of Lac Seul is 354.61 m (1163.4 ft), a 15^th percentile level, below the normal range for this time of year. The lake level remained stable over the last week and is expected to increase by 18 to 27 cm (7 to 10 in) over the next week. Lac Seul authorized outflow is 150 m³/s, with no changes scheduled.

A low pressure system will impact the northern areas of the Winnipeg River basin this evening and into tomorrow. Freezing rain and snowfall are expected along the English River, around Lac Seul and up to Lake St. Joseph. With tributary flows showing minimal response to rainfall earlier this week, Lac Seul outflow is being reduced once more to ensure rising levels.

In the southern areas of the basin freshet is progressing. Inflow to Lake of the Woods increased over the last week and lake levels have started rising. Visit the USGS HIVIS (Hydrologic Imagery Visualization and Information System) for the Big Fork River at Big Falls, Minnesota to see how conditions have evolved over the last month in a time laps video at the gauge. For updates and images of ice conditions on Lake of the Woods, the Lake of the Woods Ice Patrol has started posting regular updates.

The current level of Lake of the Woods is 322.49 m (1058.0 ft), a 35^th percentile level, within the normal range for this time of year. The average lake level increased by 5 cm (2 in) over the past week and is expected to increase by 6 to 8 cm (2.4 to 3 in) over the next week. Lake of the Woods authorized outflow is 200 m³/s, with no changes scheduled at this time.

The current level of Lac Seul is 354.60 m (1163.4 ft), a 15^th percentile level, below the normal range for this time of year. The lake level remained stable over the last week and is expected to increase by 3 to 6 cm (1 to 2.4 in) over the next week. Lac Seul authorized outflow will be reduced to 150 m³/s on Thursday, April 16^th.