LEVELnews: Great Lakes and St. Lawrence River water levels, December 2022
Lake Superior Basin experiences wet November
During November, the Great Lakes Basin experienced the following:
- The mean monthly water levels of all the Great Lakes were above average, except for Lake Ontario, which was below average.
- Lake Superior experienced much higher than average precipitation. Lakes Michigan-Huron and Erie received less than average precipitation, while Lake Ontario received close to average precipitation.
- Lake Superior experienced its second highest November water supplies on record, whereas Lakes Michigan-Huron and Erie experienced dry conditions. Lake Ontario experienced average water supply conditions.
- Lake Superior experienced its second highest water level rise during the month of November. Lakes Michigan-Huron and Erie decreased more than average throughout the month. Lake Ontario experienced its seventh largest November rise on record.
Relative to their beginning-of-December levels and with average water supplies for this time of year, some of the lakes are expected to continue their seasonal decline while others may hold steady or begin their seasonal rise in the coming months. Although, Lake Ontario may have already started its seasonal rise. Typically, Lakes Superior and Michigan-Huron should continue their seasonal decline for a few months before starting to rise again.
With water levels remaining above average in some lakes, and the possibility of large storms and winds, low-lying areas are at risk for accelerated coastline erosion and flooding. For current information and forecasts, please refer to the sources listed below.
| Lake | Levela | Compared to November monthly average (1918–2021) | Compared to November 2021 | Compared to record high (1918-2021) | Notes |
|---|---|---|---|---|---|
| Superior | 183.48 m | 12 cm above | 22 cm above | 29 cm below | - |
| Michigan–Huron | 176.41 m | 15 cm above | 21 cm below | 82 cm below | - |
| St. Clair | 174.94 m | 20 cm above | 34 cm below | 68 cm below | - |
| Erie | 174.02 m | 23 cm above | 38 cm below | 60 cm below | - |
| Ontario | 74.55 m | 15 cm below | 46 cm below | 78 cm below | - |
a Water levels are referenced to International Great Lakes (Vertical) Datum 1985 (IGLD85). For more information, please visit International Great Lakes Datum Update – Great Lakes Coordinating Committee
| Lake | November lake level change (1918–2021) | November monthly average change (1918-2021) | Compared to average November change (1918-2020) |
Notes |
|---|---|---|---|---|
| Superior | 5 cm rise | 5 cm decline | Rose more than average | 2nd largest November rise |
| Michigan–Huron | 8 cm decline | 4 cm decline | more than the average decline | - |
| St. Clair | 15 cm decline | 7 cm decline | more than the average decline | - |
| Erie | 8 cm decline | 4 cm decline | more than the average decline | - |
| Ontario | 6 cm rise | 3 cm decline | Rose more than average | 7th largest November rise |
a Lake level changes are based on the differences in levels at the beginning of the months and not the monthly average levels.
| Lake | Levela,b | Compared to November beginning-of-month average (1918–2021) | Compared to November 2021 | Compared to record high (1918-2021) | Notes |
|---|---|---|---|---|---|
| Superior | 183.57 m | 17 cm above | 30 cm above | 25 cm below | - |
| Michigan–Huron | 176.58 m | 12 cm above | 21 cm below | 81 cm below | Lowest since 2013 |
| St. Clair | 175.22 m | 18 cm above | 35 cm below | 79 cm below | - |
| Erie | 174.28 m | 19 cm above | 38 cm below | 65 cm below | - |
| Ontario | 74.37 m | 10 cm below | 46 cm below | 77 cm below | - |
a At the beginning of December, all of the Great Lakes were at least 18 cm above their chart datum level. Chart datum is a reference elevation for each lake that provides more information on the depth of water for safe boat navigation on the lakes. For more information, please visit Low Water Datum – Great Lakes Coordinating Committee.
b Water levels are referenced to International Great Lakes (Vertical) Datum 1985 (IGLD85). For more information, please visit International Great Lakes Datum Update – Great Lakes Coordinating Committee
Water levels forecast
Lake Superior is currently above its average level and is expected to remain so under most water supply conditions.
Lake Michigan-Huron is expected to remain above average under most water supply conditions.
Lake Erie levels are expected to stay above average under most water supply scenarios.
Lake Ontario levels are below average and are expected to remain so under typical or drier than average water supply conditions within the next few months. Water levels could move above average if wetter than typical water supply conditions are experienced.
For more information on the probable range of water levels, consult the LEVELnews note on projections.
For a graphical representation of recent and forecasted water levels on the Great Lakes, refer to the Canadian Hydrographic Service’s monthly water levels bulletin.
| Lake | Precipitation (percentage of LTA)a,b | Net basin supply (probability of exceedance)c,d | Outflows (percentage of LTA)a |
|---|---|---|---|
| Superior | 141% | Less than 1% (2nd highest on record) | 117% |
| Michigan-Huron | 70% | 73% (dry) | 109% |
| Erie (including Lake St. Clair) | 62% | 64% (dry) | 109% |
| Ontario | 94% | 49% (average) | 97% |
a As a percentage of long-term average (LTA).
b United States Army Corps of Engineers (GLP-LastMonth.pdf (army.mil))
c <5% extremely wet; <25% very wet; <45% wet; 45-55% average; >55% dry; >75% very dry; >95% extremely dry.
d Please refer to the LEVELnews What is net basin supply for a description of net basin supply.
Note: The figures contained in this report are provisional and are subject to change. Data are calculated from the best available observations at the time of posting.
Buffalo, New York lake effect snow event
A lake effect snowstorm hit the eastern end of Lake Erie around Buffalo, New York from November 17th to the 19th, resulting in over 1.5 m of snow in some areas. Additionally, more than 0.3 m of snow hit the region on November 19th and 20th. Lake effect snow is common in the Great Lakes Basin during fall and winter. This is due to cold air masses passing over the warmer lakes, transferring moisture into the air (or the lower portion of the atmosphere). As the air rises, it forms clouds that grow into narrow bands and produce large snowfall amounts.
Several factors played a role in the magnitude of the recent storm, including Lake Erie’s water temperature and the first large prolonged breakout of cold air in the season. To learn more about the effects of this event on the lake, please refer to the following figure, which shows Lake Erie’s water temperature, evaporation from the lake surface, and water level throughout the month of November.
Long description
Long description: Graph showing Lake Erie evaporation, water temperature, and water level throughout the month of the November. The horizontal axis is the day in November and there are three vertical axes, one in blue showing the water level, one in grey to show the lake temperature, and one in orange indicating the lake surface evaporation. Lake levels, shown with a blue line, start November relatively stable and the sharply drop around November 14th and remain lower for the rest of the month. Evaporation shown with orange bars, increases from November 7th to a peak on November 19th and then sharply drops again to lower rates. Lastly, lake temperature is shown with a grey line, which starts November higher, drop near November 14th, and remains stable but lower for the remainder of the month.
After record-setting air temperatures in November in this part of the basin, the water temperature of Lake Erie was about 3°C higher than average, which is shown above in grey. The sustained cold winds along the long axis of Lake Erie and high water temperature, resulted in higher than average evaporation, as illustrated by the orange bars. The increase in evaporation is associated with a drop in Lake Erie’s water level, shown in blue. This ultimately resulted in a band of snow and the historic snowfall event.
Although lake effect snowstorms are common each year around the Great Lakes, the intensity and amount of snow from this event are typically only seen every 10 or 20 years.
Flood information
With water levels remaining high on some lakes, there is a high risk of flooding. Great Lakes water levels are difficult to predict weeks in advance due to natural variations in weather. To stay informed about Great Lakes water levels and flooding, visit the Ontario flood forecasting and warning program.
Additional information can also be found on the International Lake Superior Board of Control website, and the International Lake Ontario–St. Lawrence River Board website.
Information on current water levels and marine forecasts
Daily levels: Current daily lake-wide average levels of all the Great Lakes are available at Great Lakes - Daily Water Levels for This Month in Meters (army.mil). The daily average water level is an average taken from a number of gauges across each lake and is a good indicator of the overall lake level when it is changing relatively rapidly due to recent high precipitation.
Hourly levels: Hourly lake levels from individual gauge sites can be found at the Government of Canada Great Lakes Water Level Gauging Stations Map. These levels are useful for determining real-time water levels at a given site, however, it should be noted that they are subject to local, temporary effects on water levels such as wind and waves.
Marine forecasts: Visit the Great Lakes water levels and related data webpage under the “Wave and wind data” heading for marine forecasts and wave heights. Current marine forecasts for Lakes Superior, Huron, Erie and Ontario are available as well as text bulletins of recent wave height forecasts.
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For more information:
Frank Seglenieks (Editor) and Nicole O’Brien
Boundary Water Issues
Meteorological Service Canada
Environment and Climate Change Canada
Burlington, ON L7S 1A1
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