Wet December has water levels dropping less than usual

Water levels in our big lakes dropped less than the average last month, according to the organization responsible for managing the control works on the St. Marys River and regulating the outflow from Lake Superior into Lake Michigan-Huron.

The International Lake Superior Board of Control said in its latest update that "water supply conditions" were wet in both the lake basins in December.

As a result, Lake Superior declined by 4 cm (1.6 in) last month. The seasonal long-term average pattern is for Lake Superior to decline by 8 cm (3.1 in) in December, the board said.

Lake Michigan-Huron declined by 2 cm (0.8 in) last month, while the seasonal long-term average pattern is for Lake Michigan-Huron to decline by 5 cm (2 in) in December, according to the board.

Meanwhile, the lake-wide average water level of Lake Superior was 1 cm (0.4 in) below the seasonal long-term average (1918-2022) and 18 cm (7.1 in) below the level of a year ago.

The lake-wide average water level of Lake Michigan-Huron was 11 cm (4.3 in) above the seasonal long-term average and 1 cm (0.4 in) above the level of a year ago.

For Lake Superior water levels at the beginning of January, the record high is 183.76 metres (602.89 ft.) set in 1986, according to board figures. The current level is 183.36 metres (601.57 ft.) which is basically at the historical average from 1918 to 2022 of 183.37 (601.61 ft.).

Over on Lake Huron and Lake Michigan, the current water level is 176.44 metres (578.87 ft.). The record high for this time of year for Huron-Michigan water levels based on 1918 to 2022 records is 177.26 metres (581.56 ft.) set in 2020. 

The board noted the MacArthur Lock has been closed and will reopen April 24. The Poe Lock will close for the winter on Jan. 15 and will reopen on March 25.

The closures are routine for winter and allow for maintenance work, the board said.

The board said the compensating gates are being maintained at a "typical winter setting".