2019-Aug-04
August 4 Water Levels Report
The Great Lakes basin precipitation was 17% below average in July, the first month since March that the Great Lakes experienced below average precipitation.
The water levels of the Great Lakes continue to be considerably above average. Lakes Superior, St. Clair, Erie and Ontario are above their record high August monthly mean levels by 1 to 6 inches, while Lake Michigan-Huron is 2 inches shy of its record high August monthly mean. The Great Lakes are either nearing their seasonal peaks or have already started their seasonal decline. Lakes Michigan-Huron, Erie, and Ontario are 1, 3, and 7 inches respectively, below their levels of a month ago. Lake Superior’s level is an inch above what it was a month ago, whereas Lake St. Clair is near its level of a month ago. Looking a month into the future, Lakes Superior, Michigan-Huron, St. Clair, Erie and Ontario are projected to be 1, 2, 5, 7 and 11 inches, respectively, below their current level.
Lake Superior’s outflow through the St. Marys River and the Lake Michigan-Huron’s outflow through the St. Clair River are predicted to be above average for August. Outflows from Lake St. Clair through the Detroit River, and outflows from Lake Erie outflow into the Niagara River, are also projected to be above average in August. Likewise, Lake Ontario’s outflow through the St. Lawrence River is forecasted to be above average for August.
Water levels shown are still-water surface elevations over the entire lake surface. Water levels at specific locations may differ substantially in accordance with wind conditions. High water levels and potentially record high water levels are expected to persist for at least the next six months, so flood prone areas are expected to remain vulnerable.
