Jan. 11, 2021 – One of the most interesting weather data sets is NOAA’s daily report on current ice conditions in the Great Lakes. Through NOAA’s Great Lakes Environmental Research Laboratory (GLERL), near real-time data is available as well as historic data for a cool way to compare winter seasons.

The data has been collected since the early 1970s and is an international collaboration of the United States and Canada.

According to GLERL, understanding the major effect of ice on the Great Lakes is crucial because it impacts a range of societal benefits provided by the lakes, from hydropower generation to commercial shipping to the fishing industry.

Historical Ice Data
The following data includes the date of maximum ice cover on the Great Lakes (all five lakes combined) and the percent of ice cover on that date that represented the maximum for that year.

2013 – 38.4 percent ice cover on February 18
2014 – 92.3 percent ice cover on March 6
2015 – 88.8 percent ice cover on March 1
2016 – 33.8 percent ice cover on February 15
2017 – 19.4 percent ice cover on March 27
2018 – 69.0 percent ice cover on February 11
2019 – 80.9 percent ice cover on March 9
2020 – 19.5 percent ice cover on February 21

Ice Fishing

Ice fishing is a popular winter sport but also a dangerous one if done on thin ice. Walking on thin ice takes on a literal meaning when people decide to drop a fishing line into one of the five Great Lakes by cutting a hole in the ice. If the ice is too thin, there is a good chance they will be in the water with the fish. The human body cannot survive long in frigid water so it is incredibly dangerous to fall into icy water, especially if not dressed with clothing designed for being submerged in cold water.

The five Great Lakes are Lake Erie, Lake Ontario, Lake Huron, Lake Michigan and Lake Superior.

When is it safe to walk on ice? The short answer is: NEVER! The Minnesota Department of Natural Resources states that ice is never 100 percent safe. And people in Minnesota know a lot about ice!

The state agency does not publish data on ice thickness because there is not a sure answer as to when ice is safe.

As stated on their website, “You can’t judge the strength of ice just by its appearance, age, thickness, temperature, or whether or not the ice is covered with snow. Strength is based on all these factors – plus the depth of water under the ice, size of the water body, water chemistry and currents, the distribution of the load on the ice, and local climatic conditions.”

The best advice then is to enjoy the beauty of the ice from the shore and buy fish at the store!

REVIEW QUESTIONS

1. What are the five Great Lakes?

2. What was the maximum ice cover on the Great Lakes in 2014? On what date did that occur?

3. When is ice safe to walk on?

4. What is hydropower?

INQUIRY QUESTIONS

1. What is the message about ice safety from the Minnesota Department of Natural Resources?

2. Why do people in Minnesota know a lot about ice?

3. How do the many factors regarding ice strength relate to one another? Choose two to discuss.

4. Create a table of the data in the story. What conclusions can you draw from the data?

5. What is the figurative meaning of “on thin ice?”