Ice Report

Minnesota winters are warming faster than global averages, and that has implications for the state’s cherished lake ice season. To learn more, MCV caught up with Kenny Blumenfeld, senior climatologist at the Minnesota Department of Natural Resources’ State Climatology Office. Blumenfeld collects and analyzes weather and climate data to help Minnesotans understand how the state’s climate is changing. He says all signs point to continued winter warming in Minnesota, with likely impacts on not just ice recreation, but also on wildlife and the environment in general.

Q | How is climate change affecting Minnesota’s lake ice?
In the last five to six decades, Minnesota has seen a two-week reduction in the lake ice season—the period between ice-on and ice-off on a lake. Some parts of the state are losing ice cover faster than others, but around Minnesota, we currently have an average of two fewer weeks of annual ice cover than we did 60 years ago.  

Q | What is the rate of warming for Minnesota winters? 
On average since 1970, winter has warmed in Minnesota by about 5.5 degrees Fahrenheit give or take, with more in the north and less in the south.

Q | That sounds alarming.
That’s very fast. By contrast, summer, the period June through August, has warmed by a little over 1 degree Fahrenheit. Minnesota is one of the fastest-warming parts of the country and has some of the strongest winter warming in the country. We stand out a little bit in that way, but the pattern of winter warming faster than summer is common throughout our continent.

Q | Is the warming rate increasing over time?
Minnesota’s warming rates vary by both season and area. All of our seasons are warming, but winter is warming three to five times faster than summer. Fall warming has really taken off recently, which can delay ice-in. Also, northern Minnesota is warming faster than southern Minnesota.

Q | With shorter ice cover seasons, do you also see that ice isn’t getting as deep?
In general, the years that have deep, high-quality ice tend to be longer ice seasons. Usually, the short ice seasons are characterized by lower-quality ice and not as much depth.

Q | Will this be a continuing trend? 
All the evidence that we have indicates these declines will continue. We expect that trend to continue so that in 20, 30, 40 years we will see lake ice seasons that are even shorter than what we’re seeing now.

Q | Does that mean it will become increasingly more dangerous to recreate on ice? 
Generally, when you have those shorter seasons, the overall danger increases because you have a shorter period with high-quality, stable ice.

Q | How else can less ice affect lakes? 
When you have less lake ice, when you change the amount of lake ice that’s present on a lake over the year, you are changing the amount of sunlight that makes it into the lake, and that alters the patterns of heat distribution in the lake. Others in the DNR are very interested in how these changes can affect both aquatic plants and fish.

Q | Are we beyond the tipping point in terms of reversing course on climate change?
If Minnesota makes all the changes that it has committed to making on climate action, then we would be considered a good team player. But we are just one player on a huge team. And what we need is the whole team to be good. That’s global. The changes that Minnesota can make would be important, but they might not be detectable unless we saw all the other states and all the other parts of the world making similar changes.