Due to significant rainfall coupled with a cool, late spring, the inflow to Namakan Lake was well above normal in May and has been maximum of record to date in June (for this time of year). Inflow to Rainy Lake was also well above normal in May and has been mostly at the 95 percentile rate (1 in 20 year high) in June to date. As a result, the levels of both Rainy and Namakan lakes and the Rainy River are currently well above normal. The dams at the outlets of both lakes are fully open.

Namakan Lake rose above its Upper Rule Curve (URC) on May 13 and is currently 26 cm (10.2 in) above the highest point on this curve. The URC is the upper limit of the normal operating band specified for the lake by the International Joint Commission. The current lake level is 1 cm (0.4 in) higher than the peak level reached in 2002 but is 25 cm (9.8 in) lower than the 2001 peak. The lake rose only 4 cm (1.6 in) over the past week and may be close to peaking, subject of course to more rainfall.

Rainy Lake also rose above its URC on May 13 and is also currently 26 cm (10.2 in) above the highest point on this curve. The lake is now 6 cm (2.4 in) above the level it reached in 2005 but is still 55 cm (21.6 in) below the level it reached in 2002. Rainy Lake rose 14 cm (5.5 in) over the past week and is still rising strongly, with inflows currently about 20 percent larger than the outflow capacity of the dam. The lake will continue to rise in the near term and its ultimate peak level will depend on the amount of rainfall received over the next few weeks.

The Rainy River is currently 2.7 m (8.7 ft) above its median level at this time of year below the Fort Frances – International Falls dam and is 2.5 m (8.1 ft) above median at Manitou Rapids. These high levels, which are due to the Rainy Lake dam being fully open and local tributary flow being high, are similar to the levels reached in 2005 but are over 1 m (3.3 ft) lower than those experienced in 2002.