Cold Climate Conditions Necessary For Ice Formation in the Mississippi River
The Mississippi River is the fourth longest river in the world and the longest in the USA. It is well known for its warm, humid climate, so it is not often that it would be cold enough for the river to freeze over. For the Mississippi River to freeze over, conditions such as extreme cold temperatures, no underlying sources of warmth, and long standing periods of cold would be necessary.
The Mississippi River is generally a warm river, even in summer it has a temperature of around 76°F at the surface. The flow of the river keeps it from freezing, as any cold temperatures that would cause the river to freeze over would be offset by the water in motion. Since the river depth is approximately 200 feet, the temperature below the surface remains quite warm year round. Without a disruption of the warm currents, like changes in wind patterns, it is difficult for the river to become cold enough to freeze.
The United States Geological Survey hydrologists did observe ice beginning to form upstream from St. Louis in January of 2018, but the buildup of ice was only in the shallower waters close to the banks. In 2006 there were also reports of ice forming in some parts of the river, though only around the edges and as small floes. In both cases, observation of the temperatures revealed that the river surface was not at a point of freezing.
So while the Mississippi River may experience intermittent freezing of the shallower waters closer to the banks, the chances of it freezing from shore to shore are slim. This isn’t to say conditions such as those observed in January 2018 cant happen again, as wind patterns, colder temperatures, and other factors could all play a part in freezing the waters of the Mississippi River. However, given the current temperature and depth of the river, observations and data suggest that the likelihood of the Mississippi River becoming frozen over is low.
Wind Patterns and Mississippi River Flows
Wind plays a role in river temperatures and has a direct effect on the Mississippi River. When the winds blow up river the current is slowed and warms the incoming water. This can produce a layer of warmth across the surface that may help keep the river from freezing when temperatures are near their lowest. On the other hand, when the wind blows down river it breaks the surface tension of the water and increases the flow. This gives the water temperature a cooling effect as the warm water is pushed away and colder water is brought in.
The annual flow of the Mississippi River varies with its peak in April, though the spring and summer months are the ones that observe the highest variations in flow. The spring and summer months are the ones most likely to see days of higher and lower temperatures, with the variations in flow providing an opportunity for the river to become colder, though still not cold enough to freeze over.
In January 2018, it was observed that when the wind blew up river, it created a barrier of warm air between the two sides of the river and enabled the water to remain unfrozen. Even when temperatures dropped to near 0°F, the warm air bar, created by a heavy flow of wind up river, kept the Mississippi from freezing. This shows that while the power of wind can cool the waters, it can also warm it.
Observations become important here as the wind patterns play a large part in the freezing of rivers, including the Mississippi. The 2017/2018 winter saw record low temperatures and extreme winds and conditions such as these can cause local wide freezes of rivers, which is exactly what happened in January 2018.
Snowfall and Ice Accumulation in the Mississippi River
The 2017/2018 Winter was also notable for its heavy snowfall, with some parts of the Mississippi receiving over two feet of snow. This was followed by the 4th coldest January on record for Minnesota, Wisconsin and Michigan. The heavy snowfall may have caused ice to form in the shallower edges of the river, but deeper waters continued to flow in most cases. This is due to the warming effect of the snow on the surface of the river, as the snow lowered the air temperature and then melted on the warmer surface of the river.
When temperatures and snowfall remain constant over a long period of time, the odds for the Mississippi River to freeze over increases. When temperatures remain cold and snowfall remains steady over a long period of time, conditions such as those seen in January 2018 may repeat themselves. This is due to the snow accumulation on the river keeping the water cool enough to freeze and create thinner ice layers that can be used as a platform on which more snow may accumulate. This platform enables more snow to be pushed into the river, acting as a lid on the river and keeping it from becoming too warm.
The depth of the river plays a role in the formation of ice here as in order for the river to freeze over it would need shallower waters for the ice to build on. When the waters are deeper and the flow is steady, the ice only accumulates on the edges of the river which then gets broken up by the current. This prevents the larger floes of ice that form in shallower waters to accumulate and form a platform on which more snow and ice can accumulate.
Can the Mississippi River Become Frozen?
Given the current temperature of the Mississippi River and its depth, the chances of its waters becoming frozen are quite low. For the water to freeze it would need an extreme change in air temperature and precipitation, with the resulting large floes of ice backed up in the river causing a decrease in its depth. However, with the temperatures in the region dropping as low as 55.0°F in recent years, there are chances of the Mississippi River to freeze over in winter.
As the depth of the river decreases, it does become easier for the river to freeze over. If temperatures were to drop below 32°F and there was sustained snowfall, the cooler temperatures could encourage the floes of ice to accumulate, especially if the conditions were just right and a cold layer of air built up on the surface. Conditions such as these will be necessary to keep the river from becoming warmer, enabling the ice to expand and create a larger platform on which more snow and ice can accumulate to freeze the Mississippi River.
Future Predictions Of Freezing Mississippi River
While record low temperatures have been observed in the region of the Mississippi River, with temperatures as low as -35°F observed in some parts, predictions and climate data suggest that future winters will not be as cold as they have been in the past. With global warming and the increase in average temperatures, both the winter and summer temperatures of the Mississippi River are expected to rise, leading to a decrease in the overall freezing rate of the river. This is also due to the increasing depth and decreasing flow of the river.
While the current temperatures are not low enough for the Mississippi River to freeze over, the possibility is still there if the correct conditions present themselves. If temperatures and snowfall remain constant, the chances of the river becoming frozen do increase, though this is only likely to happen if the temperatures reach lower than current levels and the wind patterns support the cooling process. Overall, the Mississippi River does have the potential to become frozen under certain circumstances, though the likelihood is relatively low.
Ecological Impact Of Mississippi River Freezing
Any large scale freezing of the Mississippi River can cause both positive and negative ecological impacts. On the one hand, the formation of ice sheets can create shelter for birds and other animals that reside close to the river. The ice also reduces the flow of the river, leading to high water levels, which can support river navigation in winter. On the other hand, lower water levels can have a negative impact on habitats, as more land is exposed and water resources are reduced.
The long standing cold temperatures of a frozen river can also have a negative effect on some species of fishes that require warm water to survive. This can cause a decrease in the number of species living in the water as some species are unable to survive in the cold. It should also be noted that, although snow and ice can help keep the river cold and block the winds from disrupting the cold air, any snow and ice accumulation can also reduce the amount of sunlight that reaches the river surface, making it difficult for some species to feed and survive.
The freezing of the Mississippi River has potential ecological implications if it were to become a regular occurrence, though with the current climate trends that possibility seems slim. If the river did become frozen, the effects of the decreasing temperatures and changing weather patterns would need to be monitored and managed to reduce any potential ecological impacts.
Interventions To Reduce Freeze Risk of Mississippi River
Various measures can be taken to reduce the chances of the Mississippi River becoming frozen. To counteract the potential decrease in water levels caused by ice accumulation, regular cleanups of the river can be organized, as debris, weeds and other organic material can interfere with water flow and cause the river to become stagnant and slower. This helps maintain the overall flow of the river and keeps it from becoming too cold.
Utilizing wind patterns for river cooling can also be beneficial, as changing the wind patterns to blow upstream counteracts any warm air buildup by replacing it with colder air. While this can have a cooling effect on the water, it should be noted that this only works when the winds are blowing in a certain direction and the temperature of the water remains above freezing. Sustained and low wind speeds, combined with a drop in temperatures, can push the river to freezing conditions.
It is also important to monitor snow buildup and ice accumulation along the edges of the river. If conditions allow for floes of ice to form, these should be monitored and broken up as needed to prevent any further buildup of snow or ice. Furthermore, any ice accumulation that does occur should be cleared away and melted as quickly as possible to prevent it from disrupting river flows.
In conclusion, the Mississippi River is generally a warm river and the chances of it becoming frozen are quite low. For the waters of the Mississippi River to freeze over, extreme changes in temperature and precipitation would need to occur, combined with the right wind patterns and ice accumulation. While this is possible, the current climate trends suggest that the chances of the river becoming frozen are relatively low.
