ARMY CORPS OF ENGINEERS WEEKLY GREAT LAKES WATER LEVEL UPDATE

May 03, 2024

WEATHER CONDITIONS

Temperatures last week in the Great Lakes basin rose through Saturday before remaining relatively stable through Wednesday. Temperatures for the week were above average for most of the basin, except around Lake Superior. The Great Lakes basin experienced light precipitation each day throughout the last week. This was a result of weekly rainfall accumulations well above average around Lake Superior. While the week was much drier than normal in the Erie and Ontario basins, these areas also received some rainfall. Temperatures will remain above average from Friday through Monday, with most regions of the basin having forecasted highs of 65-75 degrees Fahrenheit over the weekend. The modest rain showers of the past week will likely continue through the weekend, with most parts of the basin forecasted to receive up to an inch of rainfall by Monday.

LAKE LEVEL CONDITIONS

The forecasted lake levels for May 3^rd are 4 to 7 inches above what they were in early April for all lakes. Additionally, all lakes are at or below last year’s levels. Lakes Michigan-Huron and Erie are slightly below levels of a year ago, by 4 and 2 inches, respectively. Lakes Superior and Ontario have dropped more significantly, at 12 and 14 inches below last year. Lake St. Clair has a projected level approximately equal to last year. Lakes Superior, Michigan-Huron and Ontario are all projected to stay close to May long-term average levels, while Lakes St. Clair and Erie will be above average levels by 10 to 11 inches. By next month, Lakes St. Clair and Erie are projected to stay near their current level. The other lakes are projected to rise by 3 inches. For more information please see our Daily Levels web page.

FORECASTED MONTHLY OUTFLOWS/CHANNEL CONDITIONS

Lake Superior’s outflow into the St. Marys River is expected to be slightly below average for May.  Lake Michigan-Huron’s outflow through the St. Clair River and Lake St. Clair’s outflow into the Detroit River are projected to be slightly above average for May. Lake Erie’s outflow through the Niagara River, and Lake Ontario’s outflow from the St. Lawrence River are projected to be above average in May.

ALERTS

Water levels shown are still-water surface elevations over the entire lake surface. Water levels at specific locations may differ due to meteorological influences. Official records are based on monthly average water levels and not daily water levels. Great Lakes, connecting channels, and St. Lawrence River users should keep informed of current conditions before undertaking any activities affected by changing water levels. Mariners should use navigation charts and refer to current water level readings. Find ice information at National Ice Center’s website.

SUPERIOR

MICH-HURON

ST. CLAIR

ERIE

ONTARIO

Forecasted Water Level for May 3, 2024 (feet)

601.44

579.23

575.52

572.87

245.90

Chart Datum (feet)

601.10

577.50

572.30

569.20

243.30

Difference from chart datum (inches)

+4

+21

+39

+44

+31

Difference from average water level for Apr 3, 2024 (inches*)

+4

+6

+7

+6

+7

Difference from average water level for May 3, 2023 (inches*)

-12

-4

0

-2

-14

Difference from long-term monthly average of May (inches)

-2

+2

+10

+11

-3

Difference from highest monthly average of record for May (inches)

-18

-32

-22

-19

-33

Year of highest recorded monthly mean

2019

2020

2020

2020

2017

Difference from lowest monthly average of record for May (inches)

+22

+32

+39

+46

+33

Year of lowest recorded monthly mean

1926

1964

1934

1934

1935

Projected net change in levels by Jun 3, 2024 (inches)

+3

+3

0

0

+3

ALL DATA SHOWN IN THIS SUMMARY ARE REFERENCED TO IGLD 1985

*VALUES FOR SPECIFIC DAY ARE BASED ON 3-DAY DAILY AVERAGE AROUND SPECIFIED DATE

LONG TERM AVERAGE PERIOD OF RECORD, 1918-2023

FORECASTED INFORMATION PROVIDED BY

RECORDED DATA (1918 – present)

FOR MORE INFORMATION VISIT

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