LEVELnews
Volume 19, Number 6
14 June 2011
Online Access to LEVELnews Has Improved
Readers can once again view LEVELnews either directly online, or by accessing its PDF version without needing to provide their email address. In addition, the PDF version has a new look.
Water Levels Update
Water levels increased by more than average amounts on each of the lakes during May. The levels of lakes Superior and Michigan–Huron increased slightly more than average, while lakes St. Clair, Erie and Ontario experienced increases much larger than average. This was due to the above-average precipitation amounts that their basins received during the month.
Lake Superior’s level rose by 14 cm this May, compared to its average May rise of 10 cm. Similarly, the level of Lakes Michigan–Huron rose by 14 cm in May, which is 6 cm more than its average May rise of 8 cm.
In comparison, Lake St. Clair’s level rose by 17 cm last month, 10 cm more than its average May rise of 7 cm. Lake Erie rose by 24 cm during the month, almost five times more than its average 5 cm rise in May. Lake Ontario’s level rose by 33 cm, compared to the average May rise of 8 cm.
If there are typical water supply conditions, the levels of lakes Superior and Michigan–Huron are expected to continue their seasonal rise during June. The levels of lakes St. Clair, Erie and Ontario are expected to decline, which is typical for them at this time of year. The most probable water supplies forecast indicates that Montreal Harbour's monthly mean level will be lower than it was in May, but still above average for June.
For a complete range of probable water levels over the next six months on each of the Great Lakes, on Lake St. Clair, and at Montreal Harbour, please refer to the May 2011 edition of the Canadian Hydrographic Service’s monthly water levels bulletin.
| May 2011 Monthly Mean Level | Beginning-of-June 2011 Level | |||
|---|---|---|---|---|
| Lake | Compared to Monthly Average (1918–2010) | Compared to One Year Ago | Compared to Beginning-of-Month Average (1918–2010) | Compared to One Year Ago |
| Superior | 32 cm below | 4 cm below | 31 cm below | 2 cm above |
| Michigan-Huron | 39 cm below | 3 cm below | 34 cm below | 4 cm above |
| St. Clair | 3 cm above | 18 cm above | 11 cm above | 24 cm above |
| Erie | 16 cm above | 25 cm above | 28 cm above | 35 cm above |
| Ontario | 22 cm above | 52 cm above | 33 cm above | 64 cm above |
May Precipitation over the Great Lakes* | |||
|---|---|---|---|
| Great Lakes Basin | 119% | Lake Erie | 201% |
| Lake Superior | 91% | (including Lake St. Clair) | |
| Lakes Michigan-Huron | 102% | Lake Ontario | 140% |
May Outflows from the Great Lakes* | |||
| Lake Superior | 74% | Lake Erie | 106% |
| Lake Huron | 89% | Lake Ontario | 106% |
*As a percentage of the long-term May average.
NOTE: These figures are preliminary.
Be Up To Date When You Set Out
Whether you are a recreational boater or a ship’s captain, it is important to have up-to-date information about marine weather and water level conditions before you set out.
Marine Weather
You can find the information you need on current and forecasted weather, wind and wave conditions for the Great Lakes on Environment Canada’s weather website.
Water Levels
Real-time water levels on the Great Lakes, their connecting channels and the upper St. Lawrence River are available by telephone from a network of gauging stations operated by the Canadian Hydrographic Service (CHS).
Please visit the CHS website for a list of voice-announcing water level gauging stations and their telephone numbers.
- Date Modified: