Great Lakes Water Levels - February 2018The Great Lakes, their connecting waterways, and their watersheds, comprise the largest lake system on the planet. The monthly, seasonal, and annual average surface water elevations of the lakes fluctuate in response to a variety of factors. These fluctuations can have both positive and negative impacts on water dependent industries such as shipping, fisheries, tourism, and coastal infrastructure. NOAA Great Lakes Environmental Research Laboratory (GLERL) research on water levels in the Great Lakes analyzes components of the Great Lakes water cycle (runoff, over-lake precipitation, over-lake evaporation) to improve models, which are used by agencies and industry for water management planning.

High water levels continue for the upper Great LakesHigh water levels will return this summer for all lakes except Ontario. Water levels on Lakes Superior, Michigan, Huron, and Erie are above their long-term and monthly averages, making the spring rise a cause for concern. Lake Superior levels have been hovering within inches of monthly records since last summer, and the February 1st level was 37cm (14”) higher than the February long-term average (see figure at right). Fall and winter storms on Lake Superior have caused significant erosion, with more expected as levels rise in the spring. The timing and magnitude of snowmelt and spring runoff will be major factors in whether records are broken this summer. While water levels on Lakes Michigan, Huron, and Erie are not near record levels, forecasts call for them to remain above monthly average levels. To view current, historical, and projected water levels, visit www.glerl.noaa.gov/data/dashboard.

Drew.gronewold@noaa.gov Historical water level dynamics, seasonal projections

734-741-2444

Eric.j.anderson@noaa.gov Hourly and daily water level forecasts

734-741-2293

Brent.lofgren@noaa.gov Multi-decadal water level projections 734-741-2383

FOR MORE INFORMATION

Above: Current and historical Lake Superior water levels. Since summer 2017, the water level has been hovering very close to record high.

Great Lakes Environmental Research LaboratoryGLERL

Waves crashing onto Black Beach in Silver Bay, Minn during a storm in October 2017. Late fall and early winter storms have caused significant damage along the shores of Lake Superior.

Photo by Dennis Fawver, courtesy of the National Weather Service.

182.5

183.0

183.5

184.0

Lake

Sup

erio

r Wat

er L

evel

(met

ers,

IGLD

85) 183.91m (Record high − October 1985)

183.63m (Water level on February 1, 2018)

183.26m (February long−term average − 1918−2016)

182.72m (Record low − April 1926)

ForecastsObservationsmonthly average water levellong−term mean water level

(1860−2017)

−− 5%

95% ʼ3−month aheadʼ forecasts for past 13 months}

95%50%5%

−−−− }

Past Future

Lake Superior

182

183

184

598

602

606

−−−−−−

Forecast for February through July 2018

Lake Michigan−Huron

1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

173

174

175

176

177

178

568

572

576

580

584

−−−−−−

Lake Erie

−−−−−−

J F M A M J J A S O N D J F M A M J J

2017 2018

Surfa

ce W

ater

Ele

vatio

n (m

eter

s, IG

LD85

)

Surfa

ce W

ater

Ele

vatio

n (fe

et, I

GLD

85)

Lake Ontario

74

75

76

242

246

250

−−−−−−

How are water levels predicted in the Great Lakes?Forecasts of Great Lakes monthly-average water levels are based on computer simulation models, including some from NOAA GLERL, along with more than 100 years of data from past weather and water level conditions. The official 6-month forecast is produced each month through a binational partnership between the U.S. Army Corps of Engineers and Environment and Climate Change Canada. NOAA GLERL’s research on the water balance of the Great Lakes plays an important role in improving these forecasts. The most important variables are over-lake precipitation, over-lake evaporation, and runoff. NOAA GLERL is doing cutting-edge research through modeling and observations to better quantify over-lake evaporation —the most uncertain aspect of predicting lake levels. The sum of these variables (“net” supply of water to the basin) is routed through the lakes and connecting channels to produce a probabilistic water level forecast.

The official 6-month forecast generated by the U.S. Army Corps of Engineers on February 6, indicates that the water levels of Lakes Superior, Michigan, Huron, and Erie should follow their typical seasonal trends at above average levels, remaining above both their monthly and long-term averages into summer 2018. The Lake Superior forecast shows a possibility that early summer water levels could set new monthly record highs if snowmelt or spring rains in the Superior basin exceed average levels. The forecast suggests that levels on Lake Ontario will remain at or slightly above their monthly average levels. The Corps’ forecast is coordinated with Environment and Climate Change Canada each month. (www.lre.usace.army.mil/Missions/GreatLakesInformation/GreatLakesWaterLevels/WaterLevelForecast/MonthlyBulletinofGreatLakesWaterLevels.aspx).

Connect with us!Connect with us!National Oceanic and Atmospheric AdministrationGreat Lakes Environmental Research Laboratory4840 S. State Rd. Ann Arbor, MI 48108www.glerl.noaa.gov

The current outlook for Great Lakes water levels - February 2018

The uncertainty expressed in the forecast shown above is based on observed weather patterns and Great Lakes water levels, along with NOAA Climate Prediction Center’s regional forecasts. The 5% and 95% bands are expected to contain the observed water level 90% of the time.