Lake Huron Water Levels

To view a live feed of Lake Huron Water Levels, click the image below:

Image Link to Live Feed of Lake Huron Changing Lake Levels

Lake Huron Water Levels

The Tobermory water level plot presented here consists of readings averaged over every one hour period during the previous month. They are downloaded from the Canadian Hydrographic Service and compared to a highly smoothed version of Tobermory lake levels for the same time period in the previous two years.

Lake level variations are generally classified as short, seasonal and long term. Seasonal variations reflect changes in precipitation, evaporation and runoff over the course of a year. Long term variations reflect the net budget of water inflow versus outflow, climate change, and isostatic rebound.

Seasonal and long term variations are well displayed on web sites such as the NOAA dashboard. Here we are concentrating on the short term variations which take place on time scales of hours to days, and have amplitudes typically less than 15 cm. The largest variations are caused by barometric pressure changes and the storms that accompany them. Strong winds from one direction will pile water up on one side of the lake (“wind set”) and, if as often happens the wind switches direction as the storm passes over, depress water levels on that side and raise them on the other side. Once the storm passes, water sloshes back and forth in a “seiche” as it settles back to a level state. These barometric, wind and seiche variations typically take place over many hours to one or two days, have amplitudes of 5 to 15 cm., and can almost always be observed on our monthly plots.

At a harbour like Tobermory, or La Ronde on Cove Island, these changes in lake level on the outside can cause additional, superimposed, water level variations inside (or localized seiches) that depend on the shape and depth of the harbour. If you imagine the big lake outside as a long, weak spring with an attached weight which oscillates up and down slowly, and then imagine what would happen if that weight brushed up against a weight attached to a smaller and stronger spring, setting it into a much more rapid motion, you get some idea of this harbour effect. These harbour water level variations are usually measured in minutes not hours, and therefore do not usually show up on our plot made of hourly readings, but they can be quite large on occasions as local boat owners may remember!

Finally, there are tides! These can almost always be observed on our plot as small oscillations repeating roughly every 12½ hours, with heights at Tobermory averaging about 2 cm. As with seiches, the shape of a harbour and its bathymetry can influence the size of the tidal variation. Lake tides are described in more detail in the article Tobermory Tides available on this website. (See the SOK Resources Menu.)

Record Low Water Levels – CBC News

Record low water levels on the Great Lakes are costing the shipping industry and economy millions of dollars each year, say insiders.

Jack Frye, vice president of Southwestern Sales, which operates two shipping terminals in Windsor, Ont., estimates the low levels cost shipping companies $20,000 per freighter, or $500 million a year, in lost revenue.

Civilization starts around the water sources. So we have to maintain our water sources.’—Saad Jasim, former head of the International Joint Commission in Windsor, Ont.

Ed Dewling, captain of the Algoma Enterprise and a captain for 30 years, just passed through the Detroit River loaded with petroleum coke. His 222-metre freighter, which has a 24,494-tonne capacity cap, was running 907 tonnes light.

“We’re running light all the time now,” Dewling said.

Water levels are down because warmer air and water temperatures accelerate evaporation and the region hasn’t been getting as much rain or snow in recent years.

Excerpt Above From CBC website –


Chi-Cheemaun Ferry Service Faces Multiple Threats

Excerpt from From Tobermory Press. Full Article at the Tobermory Press “Daytrip Companion” Website (as of August 2013):

The iconic Manitoulin Island Ferry Service has been the Gateway to Northern Ontario since the 1930s. The current vessel, MS Chi-Cheemaun, was purpose built for the route in 1974 at the Collingwood shipyards — one of the last hulls built at that historic facility.

The Chi-Cheemaun has been everything her owners and crew could have wanted — comfortable, efficient, seaworthy, dependable. She is the largest passenger ferry on the Great Lakes.

She has become a huge part of the culture of the two ports she serves — Tobermory on the Bruce Peninsula and South Baymouth on Manitoulin Island. So it has been a source of stress on both “the Peninsula” and “the Island” that ridership has been dropping steadily for 20 years …

But just when the Ferry Service thought they had enough problems, low water levels made it worse. The beginning of the 2013 sailing season was delayed until spring run-off raised the lake into the normal range.

Excerpt from From Tobermory Press. Full Article at the Tobermory Press “Daytrip Companion” Website (as of August 2013):


Environment Canada Great Lakes Water Levels


Live Feed of Local Tobermory Weather Data available here.


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