Background of Lake Superior’s Freezing Over
Lake Superior is the world’s largest freshwater lake, and people have wondered for centuries if Lake Superior could ever freeze over. Located in the upper Midwest of the United States and Canada, this lake experiences a range of winter temperatures. But with an area of 82,400 km² and a maximum depth of 406 m, the possibility of a frozen lake seems remote. Nevertheless, Lake Superior has completely frozen over several times in the past.
The first known frozen lake occurred in 1780. William H. Keating provided his experience in his “Narrative of an Expedition to the Source of St. Peters River”, and noted that the lake was quite frozen, with only a few open spots and a depth of no more than 6 inches of ice.
The second complete freeze-over took place during the Great Famine of 1866-1867. An icy field of up to 1 m stretched from Isle Royale to Sault Ste. Marie. In the winter of 1885-1886, Lake Superior was reported to be completely frozen over for a third time.
The last and probably the most documented documented complete freeze-over of the world’s largest freshwater lake happened during the winter of 2009. During the peak of winter, the US Coastguard reported approximately 75% of the lake had turned to solid ice. The extreme cold weather around Christmas time, made the remaining parts of the lake freeze as well.
Recent Weather and Water Conditions
Today, Lake Superior is constantly monitored to assess if and when a freeze-over will happen. With the current rise in global temperatures, the lake’s water has become less likely to completely freeze over. Generally, weather analysts expect that Lake Superior is no longer able to freeze entirely in the near future, due to an increase in global temperatures and because of the lake’s vast area.
Even in the coldest of winter months, the lake’s temperature is estimated to remain above freezing point. This is because Lake Superior’s size and depth is large enough to store enough heat in the deeper parts of the lake, to prevent the surface temperature from dropping too low. In recent years, selective parts of the lake have frozen, but these patches usually thaw very quickly during the summer season.
A lake freeze has more dramatic consequences in smaller lakes. Joshua Meggitt, a professor from Michigan Technological University says, “It’s more likely for smaller bodies of water to freeze as surface area to volume decreases with size. When a lake is large like Lake Superior, the surface area decreases more slowly with increasing size, allowing warmer temperatures to penetrate to the bottom and preventing an extreme freeze.”
Impact on Biological Life and Ecology
The process of freeze-over has significant ecological consequences. During the freeze-over of the Great Famine in 1866-1867, cold temperatures and ice on the lake caused a severe decline in biodiversity, and consequently, the bottom of the food chain was affected. The death of many cold-wheat species of fauna, such as brook trout, whitefish, and others, destroyed the natural balance due to the low levels of oxygen in the water.
To this day, biologists and ecologists are careful not to make the same mistake twice. As climate change accelerates, they are taking action to preserve Lake Superior’s ecological reservoir. Marine biologists such as Drew Thompson note, “We want Lake Superior to be a living laboratory, so we must safely prevent any further environmental damage or disruption. Monitoring this process requires a lot of work, but it is essential to protect the world’s largest freshwater lake.”
Cultural Impact of the Freeze-over
In addition to their ecological impact, frozen lakes are often a source of fascination, especially to those living in northern regions. During winter months they often become a playground for human activities, such as ice fishing and other winter sports.
For the First Nations of Canada, frozen lakes are part of their culture and tradition. Local Indigenous people have practiced ice fishing for centuries, and still carry forward the ancient techniques when freezing temperatures occur. As mentioned by Daryl Wisdom, an Anishinaabe Elder from Canada: “Every winter we wait to see when the lake will freeze over so we can go fishing, it’s an exciting time for the community. It’s important for us to strengthen our cultural practices and carry forward our traditions.”
Technologies enabling Human Activity
Lake freeze are also a great opportunity for entrepreneurs and farmers. The frozen lake is a valuable pathway for transportation and commerce. During the past, the Ojibwe people created a network of trails on the frozen lake to connect their villages, while traders used ice roads to transport goods across the frozen lake and benefit from the lucrative winter markets.
New technologies have been developed in recent years to further profit from ice-covered lakes. This includes new kind of vehicles, such as the hovercraft which use air domains to skim across the ice and water. Other inventions, such as snowmobiles, provide an excellent way for people to explore and transport goods on the frozen lake.
Ice Thickness and Saftey Measures
Frozen bodies of water are attractive for recreational activities. For instance, people can enjoy ice skating or ice fishing on the lake, although some precautionary measures must be taken. Before engaging in any ice activity, lake managers take a range of measures to ensure the lake is safe enough to allow such activities and check if the ice is thick enough.
The thickness of the ice plays an important role in preventing any possible threats. Generally, thicker ice can sustain more weight and carry more people, so it is important for the safety of participants and their activities. Consequently, ice ponds need to be regularly examined to ensure the ice is thick enough for recreational activities.
Insights from Locals on Freezing Over
Local people from towns and cities around Lake Superior are experts in understanding the temperature and depth of Upper Midwest waters. According to many locals, the variations in temperatures have been noticeable and have influenced the behavior of the lake.
Karen Yoder, a local resident who lives in Grand Marais, a small port town in the Upper Midwest, says: “In my years of living here, I’ve seen multiple freeze-overs – but they weren’t as frequent as they were before. Although the temperatures were colder during the deep winter months, I noticed the overall freeze-overs were less often, compared to the past.”
Human Interfernce in the Freeze-Over Process
In addition to climate change, human activities take a toll. It is believed that the many influences from human activities, such as large ships passing through the lake and industrial activities, might affect the lake’s balance and prevent large-scale coverage. Yoder notes: “New structures like docks and harbors have become small islands on the lake, and during the winter months, the warm air around them keeps them from freezing over – making it clear that human interference is also a part of it.”
Apart from the established structures on the lake, human beings can also take part in more specific actions to prevent a freeze-over. For example, some boat owners in the region use the breaking-ice method – an activity in which they start their boat’s engine to move and stir up the waters around them. This method keeps the waters warm, holding a certain degree Celsius and preventing complete freezing.
Varying Freezing Patterns
So, even if Lake Superior were to freeze over again, how often would it occur? According to international research by the National Oceanic and Atmospheric Administration (NOAA), large scale ice coverage is expected in several areas of the lake. Unfortunately, due to the ongoing climate change, it is unlikely that the lake will freeze over entirely in the near future.
Additionally, due to the vast size of Lake Superior, it is expected that freezing patterns may vary in different areas. Some parts of the lake will have greater coverage than others, making it particularly difficult for researchers to predict accurate future ice coverings.
Conclusion of Complex Situation
The Lake Superior region is an amazing example of the complexity of our planet – and the impact of human activities on the environment. As climate change accelerates, it may become harder to predict the behaviour of the lake and its surrounding regions. Although in the past it completely froze over several times, it is unlikely that this will happen again in the near future, due to the combination of climate change, human activities and the lake’s vast size.
