MARQUETTE - The temperature of Lake Superior is pretty simply accepted as cold. It doesn't matter how warm the air is or what time of the year it is; Lake Superior will rarely be warmer than 55 degrees.
For those who scuba dive in the area, and the Upper Peninsula in general, it's a matter of making peace with the inevitability of freezing temperatures.
"The warmest I've ever dived in (Lake Superior) was 59 degrees," Marquette resident and diver Don Fassbender said. "That was a shallow dive - it was in the Sault and it was on a day where all the warm water had been blown into that area and we enjoyed probably 40 feet of it. We didn't hit a thermocline, which was nice."
Students from the beginner scuba diving class at Northern Michigan University take part in their end-of-the-year certification dive at Presque Isle recently. (Journal photo by Amanda Monthei)
NMU student Emily Goodman prepares for her dive while. (Journal photo by Amanda Monthei)
NMU student Brett Karnitz wades out of the water near Black Rocks at Presque Isle. (Journal photo by Amanda Monthei)
A thermocline is an abrupt change in water temperature at a certain depth in a lake (or any body of water). According to Fassbender, the typical depth at which the thermocline occurs is at 10-15 feet if you're lucky.
"There is typically a thermocline in the summer and the fall," he said. "You might have 50 degrees at best for 10-15 feet and under that it gets really cold, typically around the 40s.
"Ordinarily, you're going to hit a thermocline and it's going to be cold. Even with 7 millimeter neoprene on, you're going to get cold unless you're a mutant."
Fassbender has done a substantial amount of cold-water diving since starting in 1994, but he assured that nearly all diving done in Lake Superior can be considered cold water, even in July and August.
"There is almost nothing warm (in the U.P.) unless you're snorkeling on a perfectly calm day in a sheltered area," he said.
Fassbender hasn't only had experience in cold-water diving but also ice-diving, an extremity of diving that can be found in the U.P.
Ice diving is basically as it sounds- diving in ice-covered bodies of water.
"In ice diving you basically cut a hole in the ice and you scrape away a little bit of snow above the ice," he said. "You can actually see those things underwater - you look up you'll see little trails and it will lead you to your exit point.
"You don't have quite as much time underwater, so you want to be a little more conservative because you can get the bends a little easier if other factors come into play like stress."
The "bends," also referred to as decompression sickness, is the result of ascending to the surface too quickly after a dive. A stressful situation can make a diver want to reach the surface quicker, causing symptoms like painful joints and weakness or numbness of the body.
But while cold water can cause stress and disorientation, it also provides some of the best visibility of any diving condition.
"I've found the water to be a lot clearer (in ice diving)," he said. "There is less sediment to kick up, and unless there's a current, the water is going to be as clear as it can be. "We go to Bristol pit, in crystal falls, for students to get ice-diving certified. You can get 100 feet of visibility there which you will never get in Lake Superior."
Fassbender said the best visibility you will find in Superior is 40 feet, but it's typically closer to 20 on an average day. Aside from ice diving, which he only does a couple times each winter, Fassbender enjoys the hundreds of shipwrecks that Superior offers, having traveled to the Keewenaw and beyond to dive by them.
"If you're looking for shipwrecks, Lake Superior (is best) because even though it's colder, there are no zebra mussels," he said. "The Marquette underwater preserve has probably about a dozen shipwrecks but because of the bottom topography or whatever, all those wrecks are beat up. There are no real intact wrecks in our area."
Munising, on the other hand, is home to many intact shipwrecks that are open for diving, including the Bermuda, a late 1800s double masted schooner in Murray Bay.
"Any of the underwater preserves in Michigan would be my first and favorite place to dive," he said. "There are many wooden ships in the preserve that are over a 100 years old that are still intact because we don't have worms and all the things that will deteriorate a wooden vessel that they have in saltwater.
"I would prefer to vacation, believe it or not, in the Great Lakes area so I can see more shipwrecks."