Lake Superior Factoids

[GordMay]

Lake Superior Factoids:
Maximum depth1,333 feet (10 miles NW of Caribou Island)
Length 350 miles ~ Width 160 miles maximum
Elevation602 feet above sea level
Shoreline2,980 miles including islands - Surface area 31,700 square miles
Water clarity 65 - 75 feet
Water volume 440 trillion cubic feet, 3,000,000,000,000,000 gallons, or 10% of the worlds fresh surface water (One inch of water depth equals553 billion gallons)
Flushing rate400 500 years (Time required to change the water)
Detention time 191 years (average time a drop of water remains in the lake)
Flow rate into Lake Huron73,700 cubic feet per minute
Average water temperature40 degrees Fahrenheit
Calmest monthsJune and July ~ Stormiest monthsOctober and November
Maximum wave height31 feet
Ship wrecks recorded350 (over 1,000 lives lost)

[Alan Wheeler]

Detention time 191 years (average time a drop of water remains in the lake)

Hmmmm, think of that nxt time you flush the head.:-)

[Pblais]

Part of it is the watershed for lake Superior is quite small. Most of the inflow of water in a year is from rain directly falling into the lake. The second factor is as Gord points out it's 10% of the worlds fresh water.

The good news is the water is not any colder in the winter than it is in the summer. Not a place to go overboard. The swimming is quite poor except in the very few shallow areas near shore.

[Tim - Blind Squirrel]

I grew up sailing out of Bayfield, WI on Lake Superior. It is truely one of the great sailing areas of the world. It can be very remote and the water does tend to stay cold. However, the water temperature does not stay the same in the winter as in the summer. The bays, inlets, and waters around the Apostle Islands freeze over in the winter. You actully drive from Bayfield to Madeline Island on an ice road most of the winter. The main lake has only frozen completely over twice in the past 100 years. During the summer you will find water temps in the high 50's to mid 60's depending on where you are on the lake. The water is great for swimming if you don't mind the cooler temps. If you don't think it is check out the beach on Minnesota Point off Duluth, MN during a summer weekend. 100's of people in the water. It is also some of the clearist freshwater I have ever seen.

Water levels are usually directly related to the previous winters snowfall. Along Minnesota's north shore there are many rivers and creeks that feed the lake. I lived along the Lester River in Duluth, MN, and depending on the sping snow melt it was either a beautiful little brook or a raging river dumping thousands of gallons per minute into the lake.

Everyone should visit the area at least once in their life. The lucky ones will do it by boat.

[Steve Rust]

Morbid humour: We joke that the water on the open lake is so cold that a lifejacket is only good for recovering the body. In reality it is not quite that bad but I would doubt the water temp ever gets above 50-55 on the open lake. In the shallow sandy areas it will get warm enough for swimming but not every bay warms up enough for a leisurely swim. Jumping off the dock after a sauna at Thompson Island is a truely character building event, eh Gord.

Plabis is correct that the watershed is quite small but there are many, many rivers and streams running into the lake and only one outlet, the St. Mary's River. It is a truely spectacular sailing ground especially the Canadian shore. In some ways I am thankful for the short season, the remoteness, and the reputation as it keeps it from being overrun by hoardes of boaters and overdeveloped.

[sneuman]

I read somewhere a few years ago that Lake Huron and Lake Michigan are geographically the same body of water. If it hadn't been for a mistake in naming the lakes originally, Huron-Michigan would be the largest.

[Steve Rust]

Take a look at a map, Huron and Michigan are two distinct bodies of water connected by a narrow strait. I take the term "geographically the same" to mean they are at or near the same elevation. Using that logic we would have far fewer oceans than we have now. Also geologically they are quite differant from one other.

[yotphix]

Lake superior can also be surprisingly nasty, offering up waves 25 plus feet. This was a good day not to be out sailing! (This laker would be either 730 or 1000 feet long!)

[Rez]

Swimming in Superior: the current at Park Point, the bar running from Duluth to Wisconsin, normally comes from the big lake, then turns. As you mentioned, Brrrr. But sometimes the current will shift along the North shore and shallows, and sweep along Park Point. Really nice swimming. Lived there nine years. Experienced that 3 times!
Rez

[GordMay]

Originally Posted by sneuman

I read somewhere a few years ago that Lake Huron and Lake Michigan are geographically the same body of water. If it hadn't been for a mistake in naming the lakes originally, Huron-Michigan would be the largest.

Geologically and hydrologically, Michigan and Huron are the same body of water (they have the same water level), but are geographically distinct.
Counted together, it (Michigan-Huron) would be the largest fresh water body in the world, by surface area. The Mackinac Bridge is generally considered the dividing line between them.

Lake Superior, Michigan, and Huron once formed one giant lake all at the same level. Glacial rebound is making Lake Superior rise, and Michigan and Huron fall in their height above sea level. The pivot is near Sault St. Marie.

THE SEPARATION OF LAKE SUPERIOR FROM LAKE MICHIGAN/HURON
THE SEPARATION OF LAKE SUPERIOR FROM LAKE MICHIGAN/HURON

[Steve Rust]

Ahh, the internet. These photos posted by yotpix were not taken in Lake Superior. While this vessel is used on the Great Lakes it also plies the North Atlantic route during the winter. These photos were taken in Feb 1987 in the North Atlantic by the second mate George Ianiev.