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Lake Superior marine buoys give up to the minute water temperatures

Jul 29, 2020 07:20PM ● By Editor
Kids splash in Lake Superior along Park Point, a 7-mile long stretch.  Photo by Dan Kraker of MPR News.

Summer on the Great Lakes.

Water temperatures are finally warm enough for a refreshing swim in Lake Superior. Until the wind shifts.

Water temperatures in many of the Great Lakes have reached the 80-degree mark this summer. Check out the balmy water temperatures on Lakes Michigan, Huron, Erie, and Ontario.

Great Lakes water temperatures
Great Lakes water temperatures
NOAA/GLERL

But Lake Superior is a different animal. Superior’s northerly location and greater depth mean frigid waters lurk below the surface all summer long. Water temperatures have reached the 70s in the Duluth area this week. But colder pools of water lurk offshore.

Lake Superior water temperature
Lake Superior water temperature
NOAA/GLERL

And shifting winds can cause rapid temperature drops on the big lake.

Upwelling events

Lake Superior has some of the most unique geography and meteorology on the planet. A northwest wind is usually a cold wind in Minnesota. But for the North Shore, downslope warming means a northwest wind is often a warmer wind direction.

That same northwest wind that warms the air along the north shore has the opposite effect on water temperatures. As winds blow offshore, wind friction on the water surface pushes the warm surface waters away from the shoreline. That process creates coastal upwelling and pulls colder water from deeper in the lake upwards near the shore.

Coastal upwelling
Coastal upwelling
NOAA

Upwelling can produce a rapid water temperature drop near shore. Water temperatures can plunge from the swimmable 70s, to the hypothermic 50s in a short time. This buoy from McQuade Harbor shows an air temperature of 75 degrees and a water temperature of 56 degrees.

Water and air temperatures data from buoys on Lake Superior
Water and air temperatures data from buoys on Lake Superior
University of Minnesota-Duluth

So you may want to check out the latest water temperatures from the University of Minnesota-Duluth Lake Superior buoys before you decide to stick a toe (or anything else) in the water on Lake Superior.

Lake Superior nearshore buoy
Lake Superior nearshore buoy - University of Minnesota-Duluth/Large Lakes Observatory.

To read the original articles and see more, follow this link to the MPR News website:
temperatures:
https://www.mprnews.org/story/2020/07/28/lake-superior-marine-buoys-give-up-to-the-minute-water-temperatures



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