September 2026

A shift in weather patterns is expected across the Winnipeg River basin next week. Current forecasts indicate daily chances of rainfall, with the potential for heavier precipitation around mid-week. However, considerable uncertainty remains among meteorological models regarding the amount of rainfall the basin may receive. As a result, the projected range of lake level increases is relatively wide, particularly when compared to the stable lake level conditions observed over the past month.

The current level of Lake of the Woods is 322.69 m (1058.7 ft), a 15^th percentile level, below the normal range for this time of year. The average lake level declined by 1.5 cm (0.5 in) over the past week and is expected to increase by up to 10 cm (4 in) over the next week. Lake of the Woods authorized outflow is 150 m³/s with no changes scheduled.

The current level of Lac Seul is 356.37 m (1169.2 ft), a 50^th percentile level, within the normal range for this time of year. The lake level decreased by 1.5 cm (0.5 in) over the last week and is expected to increase by up to 9 cm (3.5 in) over the next week. Lac Seul authorized outflow is 200 m³/s with no changes scheduled.

---

The LWCB Basin Data page will not be updated on Wednesday, September 30 (National Day for Truth and Reconciliation in Canada). Daily data updates and publication will resume on Thursday, October 1.

Forecasts indicated dry and sunny weather for the Winnipeg River basin over the next week. In the fall, these conditions lead to increased lake evaporation. The large lakes will be losing water through evaporation over the next week and as a result, mean lake levels are expected to decline gradually.

Why is lake evaporation typically higher in the fall?

There are three main drivers for evaporation: (1) warm water temperatures coupled with cold air temperatures, (2) low relative humidity and (3) high wind speeds. In summer, the air temperature is higher than the water temperature and humidity also tends to be high. But by September, these conditions reverse. The water has warmed and its temperature can be higher than the air temperature. Humidity drops and wind speeds can increase. At Lake of the Woods, it is common in September for evaporation to remove more water from the lake than it receives from rainfall and tributaries. This means water levels would drop even if no water was flowing out to the Winnipeg River.

Sustained, high winds in recent days are also causing water levels to fluctuate significantly and can temporarily lower local water levels further. The LWCB recommends that boaters exercise increased caution around potential hazards in shallow areas.

How Wind Affects Water Levels on Large Lakes

We often think of a lake’s surface as flat and still—aside from waves. But on large lakes like Lake of the Woods and Lac Seul, wind can cause noticeable changes in water levels from one location to another. This phenomenon is called wind setup. When sustained winds blow across the lake from one direction, they push water toward the far shore, raising the water level there while lowering it on the windward side. This creates a temporary tilt in the water surface. As wind speed, direction, and duration change, so does the distribution of water across the lake.

During windy periods, the average lake level computed from the measurements around the lake may change from day to day, even though the amount of water in the lake has changed little. And because lake inflow is computed using the change in lake level over time, this instability also causes inflow values to fluctuate from day to day.

The current level of Lake of the Woods is 322.70 m (1058.7 ft), a 15^th percentile level, below the normal range for this time of year. The average lake level declined by 4 cm (1.5 in) over the past week and is expected to decrease by 1 to 2 cm (0.5 to 1 in) over the next week. Lake of the Woods authorized outflow is 150 m³/s with no changes scheduled.

The current level of Lac Seul is 356.39 m (1169.3 ft), a 50^th percentile level, within the normal range for this time of year. The lake level increased by 3 cm (1 in) over the last week and is expected to decrease by 3 to 4 cm (1 to 2 in) over the next week. Lac Seul authorized outflow is 200 m³/s with no changes scheduled.

The current level of Lake of the Woods is 322.74 m (1058.9 ft), a 15^th percentile level, below the normal range for this time of year. The average lake level declined by 1 cm (0.5 in) over the past week and is expected to increase by up to 4 cm (1.5 in) over the next week. Lake of the Woods authorized outflow is 150 m³/s with no changes scheduled.

The current level of Lac Seul is 356.40 m (1169.3 ft), a 50^th percentile level, within the normal range for this time of year. The lake level increased by 2.5 cm (1 in) over the last week and is expected to increase by 3 to 6 cm (1 to 2 in) over the next week. Lac Seul authorized outflow is 200 m³/s with no changes scheduled.

Hydro Outages at Dams

Hydro One will be conducting work on the electrical grid starting this weekend which will affect the dams at Ear Falls and Kenora. For both outages, generators will be shut off at the dams and flow will need to be passed through the spill gates. During these operations, there will be fluctuations in water levels on the Winnipeg and English Rivers.

September 12 to 14: Outage at Ear Falls

Expect a temporary water level decrease on the English River between Ear Falls and Manitou Falls, as well as at Pakwash Lake and Camping Lake. A lesser decrease in water levels is also expected directly downstream of Manitou Falls. There will be minimal impact on water levels further downstream and no impact at Caribou Falls.

September 16: Outage at Kenora

Expect levels along the Winnipeg River to fluctuate by 3 to 5 cm (1 to 2 in) on the day of the outage and potentially into the following day, as operators restore flow through the generators and close the log sluices.

Caution: These outages will exacerbate already low water levels due to the ongoing drought conditions. The LWCB recommends that boaters exercise increased caution on the outage days indicated.

A cold front brought significant rainfall to much of the Winnipeg River basin over the Labour Day weekend, with the highest amounts recorded near Kenora and Ear Falls. Rainfall directly on lakes and rivers caused local water levels to rise by a few centimetres; however, drought conditions have limited runoff, resulting in little increase in tributary river flows across the region.

The recent rises in Winnipeg and English River water levels, along with the spikes in inflows to Lake of the Woods and Lac Seul from direct rainfall on the lakes, are expected to be temporary. As drier conditions return, lake inflows and river flows are expected to decline over the coming days.

Although conditions were relatively dry over the past week, forecasts suggest a change in weather patterns early next week. A low-pressure system is expected to move across the region from Monday through Tuesday, bringing the potential for significant rainfall, particularly over the southern portions of the basin.

While precipitation forecasts beyond a few days remain uncertain, this system could produce the wettest conditions observed in the Winnipeg River basin in several weeks. If the forecasted rainfall materializes, lake inflows are expected to increase, which would lead to rising lake levels.

The Secretariat will continue to monitor conditions closely and will advise if any outflow increases are required next week.

The current level of Lake of the Woods is 322.73 m (1058.8 ft), a 15^th percentile level, below the normal range for this time of year. The average lake level declined by 2 cm (0.8 in) over the past week and, depending on rainfall amounts, may increase by up to 10 cm (4 in) over the next week. Lake of the Woods authorized outflow is 150 m³/s with no changes scheduled.

The current level of Lac Seul is 356.37 m (1169.2 ft), a 40^th percentile level, within the normal range for this time of year. The lake level increased by 2 cm (0.8 in) over the last week and is expected to increase by 3 to 11 cm (1 to 4 in) over the next week. Lac Seul authorized outflow will increase to 200 m³/s on Friday, September 4.

---

The LWCB Basin Data page will not be updated on Monday, September 7 (Labour Day). Daily data updates and publication will resume on Tuesday, September 8.