Extremely wet weather and a significant rise in Lake Superior levels will result in St. Marys River outflows being increased in November.
During a relatively wet September, Lake Superior rose 4 cm while on average Lake Superior begins its seasonal decline in September. Conditions were closer to average downstream and Lake Michigan-Huron declined 6 cm in September.
The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission (IJC), advises that the gate setting at the head of the St. Marys Rapids will be adjusted on Monday, 23 July 2018.
Conditions in the Lake Superior and Lake Michigan-Huron basins were near average last month and the seasonal water level rise continued on both lakes. At the beginning of July, Lake Superior is 11 cm above average (1918 – 2017), but 14 cm below the level at this time last year.
Lake Superior began its seasonal rise in May, but rose just 5 cm as dry conditions persisted in the basin for a third straight month. Conditions were wetter downstream, and Lake Michigan-Huron rose 11 cm last month.
Lake Superior continued its rapid decline in April as continuing high outflows combined with a second straight month of dry conditions in the basin, while more seasonable conditions returned to the Lake Michigan-Huron basin and its seasonal spring rise resumed.
Conditions were dry in the Lake Superior and Lake Michigan-Huron basins and while the water levels of both lakes declined in March, levels remain well above average. The monthly mean level of Lake Superior in March was 183.54 m, the 2nd highest on record (1918 - present) and 7 cm…