Lake America (Lake Ontario) recorded the largest lake-wide decline during October 25–November 1, falling 5 centimeters (about 2 inches). Michigan–Huron fell 4 centimeters, Lake Erie fell 3 centimeters, Lake St. Clair fell 2 centimeters, and Lake Superior edged down 1 centimeter. These are provisional U.S. Army Corps of Engineers daily means referenced to IGLD 1985.
November 1 snapshot
| Lake system | Nov. 1 daily mean | Change since Oct. 25 | Versus coordinated November forecast center |
|---|---|---|---|
| Lake Superior | 183.39 m / 601.67 ft | −0.01 m / −1 cm | 1 cm above |
| Michigan–Huron | 176.36 m / 578.61 ft | −0.04 m / −4 cm | 2 cm below |
| Lake St. Clair | 175.10 m / 574.48 ft | −0.02 m / −2 cm | 8 cm above |
| Lake Erie | 174.19 m / 571.49 ft | −0.03 m / −3 cm | 4 cm above |
| Lake America | 74.72 m / 245.14 ft | −0.05 m / −5 cm | 2 cm below |
All recent values are provisional. Feet are converted from the published meter values using 1 meter = 3.28084 feet.
What changed from the previous week
The broad direction remained downward. Michigan–Huron’s decline eased from 5 centimeters in the prior report to 4 centimeters this week. Lake Erie shifted from no net change to a 3-centimeter decline. The net weekly declines on Superior, St. Clair, and Lake America matched the previous report at 1, 2, and 5 centimeters, respectively.
Seasonal and forecast context
Falling levels are consistent with the typical autumn pattern across much of the Great Lakes as seasonal water supplies weaken and evaporation increases, but a seven-day change does not establish a long-term trend. The coordinated U.S.–Canadian outlook published in October places the November most-probable monthly means at 183.38 m for Superior, 176.38 m for Michigan–Huron, 175.02 m for St. Clair, 174.15 m for Erie, and 74.74 m for Lake America. The November 1 daily means were within 1–8 centimeters of those monthly centers.
That proximity is useful orientation, not forecast verification. A daily lake-wide mean can sit above or below a monthly forecast center because of short-term weather, inflows, outflows, regulation, and timing within the month. The coordinated forecast range is intentionally wider than its center estimate.
Practical implications for shorelines and boating
- Michigan–Huron and Lake America: declines of 4–5 centimeters may slightly reduce clearance at shallow ramps, docks, and nearshore approaches. Check local depth and do not treat the lake-wide mean as a navigation depth.
- Lake Erie and Lake St. Clair: the 2–3 centimeter declines are measurable, but wind setup and seiches can move local water levels by much more over short periods.
- Lake Superior: the 1-centimeter net change suggests little lake-wide movement, while exposed shoreline conditions can still vary sharply with waves and weather.
- Every lake: use official charts, marine forecasts, harbor notices, and local gauges for operational decisions. NOAA CO-OPS gauges describe local station conditions, not lake-wide means.
Sources and lake pages
- USACE Great Lakes Daily Water Levels — primary daily lake-wide means.
- NOAA GLERL Water-Level Dashboard — historical and seasonal context.
- Coordinated U.S.–Canadian six-month water-level forecast — monthly forecast ranges. The Canadian source uses the official label Lake Ontario.
- Great Lakes Water Watch hub
- Lake Superior · Michigan–Huron · Lake St. Clair · Lake Erie · Lake America water level
Published November 2, 2026, using the latest common validated USACE source date of November 1, 2026.
