Faced with frigid Arctic air, relentless blizzards, and other extreme elements, citizens of Minnesota have a good reason to wonder whether the legendary Mississippi River is capable of freezing over during the cold winter months. After all, the Mississippi River is a 2,553-mile long waterway that stretches from northern Minnesota down to the Gulf of Mexico, covering vast swaths of railroads and landscapes along the way. Yet despite its length and expanse, does the Mississippi River actually freeze over in Minnesota?
The short answer is yes – the Mississippi River does freeze over in Minnesota. According to the National Park Service, the river is generally frozen solid for a few winter months, typically from late December to early March. Yet while the Mississippi River freezes over in Minnesota, this cold snap doesn’t happen everywhere. Areas along the river that get more sunlight tend to stay open, whereas the northernmost parts — the very ones in Minnesota — freeze in the winter due to the area’s subarctic climate.
The process of the Mississippi River freezing over is a gradual one, experts say. When the water reaches 32°F, it starts to form thin sheets of ice known as “frazil ice”. As the water continues to cool and freeze, the sheets become thick and solid, at which point it’s considered fully frozen over.
Notably, weather is the major element for the Mississippi’s intermittently icy submersion. Specifically, when major snowstorms hit the Northland, the air temperatures usually drop below 0°F. If these unusually cold temperatures persist for several days, the river’s shallowest parts will quickly freeze over.
That said, weather isn’t the only factor in the Mississippi River freezing over. Because the river meanders through many swampy lowlands and fresh water pools in Minnesota, the strength of the current plays a major role. If the current is powerful enough, the river won’t freeze over — even if temperatures dip below freezing. Similarly, if the current is weak, or if part of the river is blocked or stalled by rocks or land, it’s very likely that part of the river will freeze over.
Ferries Along the Mississippi
The Mississippi River freezes over in Minnesota every year, but this doesn’t necessarily mean that all life along the river grinds to a halt — even during the coldest winter months. That’s because of the network of ferries that bravely run along the river, most of which are specifically designed to plow through even the thickest sheets of ice.
These ferries provide transportation for towns up and down the river, offering a unique and effective way to get around during the winter season. The ferries are staffed by expert ice breakers and captains, who know exactly how to maneuver the river without colliding with the thickest pieces of ice that form.
Despite the ferries’ best efforts, however, some of the ice carries are still forced to remain dormant over the winter. When the ice becomes too thick, even ferries can’t operate — leading many of the river’s industries to shut down for a few months until the ice melts away.
Effects of Climate Change on Freezing
While the Mississippi River does freeze in Minnesota every winter, experts suggest that climate change may be shortening the river’s icy vacation. According to a study conducted by the U.S. Fish and Wildlife Service, the Mississippi River’s ice freeze dates have been pushed up by an average of four days, with the 18.6°F ice-out date on Lake Minnetonka occurring an entire three weeks before it did in 1960.
The effects of climate change are also making it more difficult for ferries to navigate the river in the winter. With thinning ice and warmer temperatures, patches of the river that previously froze solid have started to stay open, making it nearly impossible for ferries to find a way around them. As a result, many of the ferries that keep the river’s industry alive have been forced to shut down for longer periods, further raising concerns about the longterm effects of climate change.
Environmental Benefits of Freezing
On the other hand, the freezing of the Mississippi River can also have beneficial effects on the environment. For example, frozen lands put less strain on soil and crops, as both are more resilient to cold weather than sweltering heat. Additionally, heavy snow covers the land and creates insulated blankets of white that keep the ground warm, even during the coldest of nights.
The thickness of the ice along the river also serves as an environmental advantage. As the Mississippi River freezes up, so too does the speed of its current — creating the perfect environment for the reproduction of aquatic species and native fish.
At the same time, ice also helps control water and nutrient levels along the river. When the ice melts in the spring, the water and nutrients can then be redistributed back into the environment starting from the headwaters near northern Minnesota — providing a much-needed boost to the river’s delicate ecosystem.
Unstable Ice in Minnesota
Despite these benefits, the Mississippi River freeze over in Minnesota still poses several challenges. The ice is often unstable, meaning that sudden changes in temperatures can quickly lead to shifting and cracking. Although expert ice breakers are on call to handle any disruption, such disruptions can still be hazardous — threatening to leave ferry riders stranded if they become ensnared in any of the frozen riverside outlets.
The changing climate is also causing concern amongst many Minnesota locals. According to several climate change experts, the warmer temperatures now consistently occurring along the river are ultimately creating extended ice-free zones that may eventually become permanent — ultimately changing the nature of the river and its associated industries.
Preparedness for Winter Months
At the end of the day, Minnesota’s local authorities, ferry operators, and industry experts must remain vigilantly prepared for the river’s shapshifting state — especially as winter approaches and temperatures drop once again. To aid in their winter preparedness, many of the river’s industries now use a high-tech array of satellite imaging, geographic information systems, and other remote sensing technologies to monitor the changing shape of the river. These systems are constantly gathering data and adjusting the navigation of ferries accordingly.
In the end, the Mississippi River does freeze over in Minnesota each year — and while this may lead to a few transportation dilemmas along the way, the freeze has its environmental advantages that help to keep the river running gently and healthily.
Impacts of Freezing on Local Wildlife
The freeze over of the Mississippi River has impacts across many different levels of Minnesota’s ecology — one of the most visible being local wildlife. Just as the freeze has a bigger impact in northern Minnesota as compared to other states along the river, the impact on locally living animals is also more significant.
Each winter, not only do many of the non-aquatic species head towards warmer climates, those animals living within and around the river often naively explore the newly solidified ice — which can lead to unfortunate deaths due to thin ice and unexpected holes.
Though this wintery mortality is natural, some wildlife experts have suggested that prevention techniques could be employed as a way to reduce the impact that the Mississippi River’s annual freeze over has on Minnesota’s local wildlife. As a means of prevention, educating the public on thin ice warnings has been found to be one of the most effective ways to reduce the mortality rate of these local animals.
Impacts of Freezing on Local Economies
In addition to wildlife, the freeze over of the Mississippi River in Minnesota can also have large impacts on the surrounding local economies. Not only do many of the industries along the river rely on the ferries for transport, but various agriculture and land-water based companies depend on the open water in order to survive.
One of the world’s busiest ports — the Twin Ports of Duluth and Superior — is located upstream along the Mississippi River, right near the northern tip of Minnesota. Although ice over can be an invaluable asset to this port, like all other industries, it too relies on open water to bring products in and out of the Twin Ports.
Due to this, events such as the extremely cold winter of 2013-2014 — when the entire length of the Mississippi River froze over — led to numerous temporary delays and shutdowns throughout the region. Though this wintery event was a natural part of the river’s ecology, for many, it was also an all-too-real demonstration of the impacts that climate change has on our local economies.
Future of Ice Freezing in Minnesota
As the effects of climate change become more and more apparent, it is becoming increasingly difficult to predict the future freezing over of the Mississippi River in Minnesota. As temperatures continue to increase in the region, the river has taken longer to freeze over — if at all — leading some experts to predict that eventually the river may not freeze over in Minnesota at all.
That said, the warming waters and air could have unique effects on the health of the river and surrounding ecosystems. Warmer temperatures have the potential to open up the river to a variety of underutilized aquatic species, while also helping to regulate the river’s flow — promoting a more resilient and energized river system.
Today, the Mississippi River still freezes in the winter months, but the effects of climate change have the potential to permanently shift the course of the river’s future — challenging the ecology, trading, and navigation of the generations to come.
