On September 25 the surface temp was 60 degrees, and down 45 meters the temperature was 51 degrees. That is a massive layer of warm water in a huge, coldwater lake.

As a life-long resident of Duluth, I am aware of Lake Superior and its influence on the area. A deeper interest and awareness of the lake began in the spring of ’79, when I moved into our present house near the McQuade Public Access. Twice a day I make the drive along Scenic 61 to work and back. Through the years I have memorized just about every exposed rock in the lake, witnessed waterspouts and beautiful rainbows, and have seen black bears, moose, and deer climb out onto the beach after a swim.

Last summer and into early winter, two things were very apparent. The lake level was very low, new rocks appearing almost weekly, and the water was very warm, evidenced by folks swimming in late September. For years the Big Lake dictated the area’s weather, but things seem just slightly different now.

Because of my interest in Lake Superior trolling, I am cognizant of summertime surface temperatures and the cold-water “temperature breaks” along the coast. Normally, the surface water warms first near Duluth and than gradually moves up the shore. You can chase this “break” from Duluth to Grand Marais, fishing along the way.
Last summer, the water warmed quickly and stayed warm throughout the summer and into mid-fall. Usually, the layer of warm water does not extend very deep beneath the surface. Last year, the warmth penetrated to depths of 100 feet or more.

The water entering the French River Hatchery from intake pipes extending to Lake Superior’s depths (about 65 feet) was so warm that juvenile steelhead and Kamloops rainbows were severely stressed and substantial mortality occurred. Never had the hatchery personnel seen such warm water, up to 68 degrees, for an extended time. Because of the temperatures at the intake and comments from anglers and charter captains concerning the warm water, the Minnesota DNR did a water column check for some hard facts. On September 25, off Stoney Point, the surface temp was 60 degrees and down 45 meters (147.6 feet) the temperature was 51 degrees. That is a massive layer of warm water in a huge, cold water lake.

Not only was the summer of 2006 warm (warmest July on record in Duluth), but also it was also very dry. The drought in the Lake Superior watershed led to a monthly decline in the lake’s level. The February, 2007, lake level is approaching the all-time low that dates to 1926.

The low lake levels affect shipping negatively because ships can’t haul full loads, which increases the cost of the product delivered. According to Glen Neksavil, representing the Lake Carriers Association, for every one-inch drop in Great Lakes’ water levels, ships have to reduce their cargo by 50 to 270 tons, depending on size, to avoid grounding in shallow harbors and channels.

Fishery managers are also concerned with the low water leading into spring. The water is so low that fish access to streams may be hindered due to exposed gravel bars. Anadromous trout leave Lake Superior to spawn in North Shore streams each spring. The Lester River, which has a very good spring run of both steelhead and Kamloops, is susceptible to blockage by wave-deposited gravel and small cobblestones.

If the warm and dry conditions continue into summer, the warm waters in streams will stress trout living there, including juvenile steelhead. Fish kills likely occurred last winter when severe cold completely frozen drought-stricken streams.

Late winter snowstorms dumped over 40 inches of snow in places. The snowfalls brought the winter totals to just about average and the talk of a drought subsided. The major question, though, is how much did this recent moisture really help out? The snow fell onto very frozen ground, the frost going down almost four feet in places, which lead to many septic fields freezing in both Minnesota and Wisconsin.
Within a week of receiving this snow, temperatures rose into the upper 40s to mid 50s and the snow pack began melting rapidly. Mike Stewart at the National Weather Service in Duluth reported that the snow depth dropped from over 20 inches on March 8 to less than eight inches on March 13. When snow melts on frozen ground, little-to-no moisture soaks in and most runs off and is evaporated back into the atmosphere.

Field reports from the Canadian side of Lake Superior are no more encouraging. Well below average snowfall affected the North Shore from Thunder Bay to Wawa. The hopes of a good runoff are essentially nonexistent. Substantial April rains will be needed to trigger runs of trout in the entire Lake Superior watershed and to have a positive affect on the lake’s lowering levels.