Why is the Mississippi River So Dangerous?

Written by Jennifer Haase
Updated: July 19, 2023
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Despite its majestic beauty, the Mississippi River is a dangerous place to be. It is the fourth largest river worldwide by drainage area, with a reputation for being difficult for swimmers to survive. And every year, people get hurt or drowned in her waters.

Let’s take a look at why the Mississippi River is so dangerous, then explore ways to spend time enjoying this tremendous river safely.

According to the Mississippi River and National Recreation Area, the Mississippi River is 2,350 miles long.

1. The Mississippi River Currents are Powerful

Mississippi river delta

The Mississippi River has incredibly strong currents.


According to the Mississippi River and National Recreation Area, the Mississippi River is 2,350 miles long. The average flow rate or current varies along its lengthy path. For example, one of this river’s strongest flow rates is near New Orleans at 600,000 cubic feet per second. That’s an incredible amount of strong water flow that could quickly kill a swimmer and destroy a small boat.

The general current of this river is enough danger by itself to deter people from getting in the water. However, just in case you think wearing a life jacket will keep you safe, let’s talk about the other ways these currents could cause bodily harm or death.

River Currents Can Slam You Into Docks, Boats, Trees, and Debris

The banks of a massive river can be full of dangerous obstacles like trees and debris.

©Ralf Broskvar/Shutterstock.com

Even with a life jacket on, the Mississippi River could cause a swimmer, kayaker, skier, and others terrible harm. The currents can quickly slam you into a dock, boat, tree, or any other debris in the water.

According to the National Park Service, when a fast-moving current hits an object, it pushes the water up and over it. So, even if you’re lucky enough to hit something like a tree that might break your fall, the current will quickly sweep you away before you can grab onto it. The resulting injuries could be severe, including concussions, lacerations, bruises, and broken bones.

One of the most dangerous aspects of these fast-flowing rivers is that their currents can easily carry away small boats, kayaks, and canoes. So if you’re not an experienced boater, it is best to stay out of the Mississippi River.

It’s Easy to Get Caught in an Undertow

An undertow is when the water near the shoreline flows back out to sea. This spiraling action can happen even on calm days. Undertows are extremely dangerous because they can quickly pull a swimmer out to sea and make it difficult to return to shore.

Undertows occur when currents slow down at the bottom of the river due to friction. However, the current is still flowing quickly at the water’s surface. Water then swirls in a corkscrew motion at the point where the two currents meet. This spiraling water is extreme in a massive river like the Mississippi. As a result, getting caught in an undertow is hard to survive.

According to the National Oceanic and Atmospheric Administration (NOAA), if you find yourself caught in an undertow, the safest thing to do is to relax and float. Do not try to swim against the undertow, as this will only tire you out. Instead, let the undertow carry you until it dissipates, then swim at an angle away from the shoreline to return to land.

Eddies could also pull you under the water’s surface. An eddy is a circling current of water that forms when the river’s main current hits an object. The water then flows around the object in a circle. Eddies can vary in size, from a few feet wide to miles across.

If caught in an eddy, it can quickly pull you under and trap you underwater. According to the National Park Service, the best way to escape an eddy is to swim across it, not with it.

Remember that undertows and eddies can occur even on calm days, so it is always important to be aware of the surroundings and take caution when swimming in any body of water.

2. Water Levels are Five Times Higher in the Spring

Mississippi National River and Recreation Area

River waters rise in the spring from melting snowpack and heavy rains.

©NPS/Gordon Dietzman / Public Domain – License

If you thought the Mississippi River currents were dangerous during the summer, just wait until spring. That’s because the water level of this river rises significantly during this time of year due to melting snow and heavy rains.

The water level of the Mississippi River can rise as much as five times its normal levels during the spring. This higher water level means the currents are even stronger and more dangerous. It also means there’s an increased risk of flooding.

3. Mississippi River Floods are Deadly

Discover Why the Mississippi River Once Flowed Backward for 24 Hours Cover Image

Mississippi River flooding is often deadly.

©Akarat Phasura/Shutterstock.com

The Mississippi River is susceptible to sudden flooding due to snowpack melts and heavy rains. Flooding can create a dangerous situation for anyone near the river, as the fast-moving waters can easily sweep away people, vehicles, and even buildings.

As reported by the National Weather Service, flooding is the most common natural disaster in the United States. River floods occur every year and even more in the spring. Based on records from the National Weather Service, the Mississippi River floods an average of about once every three years. However, these numbers are constantly evolving as the weather changes yearly.

Notable Flood Deaths and Damages

In June 2008, a severe flood on the Mississippi River caused over $15 billion in damage and killed at least 24 people. The flood was caused by heavy rainfall in mainly Iowa and Wisconsin, with flooding in some areas of Eastern Iowa lasting more than ten days.

More recently, in January and February 2016, another severe flood hit the Mississippi River. This time, the flood resulted in at least 20 deaths and stemmed from the strongest El Nino effect on record at the time.

And in 2019, the longest flood of the lower Mississippi occurred from Dec 2018 through August 2019. This record-breaking flood caused at least 12 deaths and over $20 billion in damages. The stunning duration of this flooding was due to multiple weather events in multiple tributary basins.

4. Some Animals Living in the River are Dangerous

Bull sharks sometimes swim up the Mississippi River from the sea.

©Fiona Ayerst/Shutterstock.com

In addition to the currents and undertows, some dangerous animals live in the Mississippi River. These include alligators, snakes, and snapping turtles. You might even run into a bull shark or two.

Alligators are a common sight in the Mississippi River. They usually stay near the shoreline and can be easily camouflaged. One estimate puts the number of alligators in this very long river at around 30,000 total. Alligators live in the more swampy areas.

Snakes are also a common sight in the river. The timber rattlesnake is one of the most dangerous poisonous snakes living in or near these waters. Other dangerous snakes of the Mississippi include the water moccasin, copperhead, eastern diamondback rattlesnake, coral snake, and pygmy rattlesnake.

Turtles aren’t usually dangerous animals, but the snapping turtle is an exception. This type of turtle is found in this river and can grow over two feet long. They are aggressive and have powerful jaws that can cause serious injury. Alligator snapping turtles are the largest turtles ever sighted in these waters.

Last but not least, there is the bull shark. This type of shark usually lives in saltwater but can also live in freshwater. Bull sharks sometimes travel up the Mississippi River and have been spotted as far north as Illinois.

5. The Mississippi River is Polluted

Pollution makes rivers dangerous for swimmers and boaters.

©Eurico Zimbres / CC BY-SA 2.5 – License

The Mississippi River is one of the most polluted rivers in the United States. This pollution is due to various factors, including agricultural runoff, sewage treatment plants, and industrial facilities.

Agricultural runoff is any water that runs off of farmland. This water can contain pesticides, herbicides, and other chemicals that can harm the environment.

Sewage treatment plants are another significant source of pollution for the Mississippi River. These plants treat human waste before releasing it into the river. However, some raw sewage still ends up in the water.

Industrial facilities are also a significant source of pollution for this river. These facilities release a variety of pollutants, including heavy metals and toxic chemicals. Though you might not feel the effect of these chemicals immediately, troubling symptoms or chronic illness could result from toxic chemical exposure.

All these factors make the Mississippi River one of the most polluted rivers in the United States.

Five Ways to Stay Safe at the Mississippi River

River cruises are a popular way to safely enjoy the Mississippi River.


There are important ways to stay safe while swimming in the Mississippi River. Here are five safety practices to consider.

  • Avoid swimming near industrial facilities or sewage treatment plants. These areas are more likely to have pollution than other parts of the river. They might also have more eddies and debris along the bank, like tires and other discarded items.
  • Avoid going into the river during the spring flood season and during periods of heavy rain. This precaution is essential because runoff from farms and other areas can wash pollutants into the river. Spring runoff from snow packs, plus heavy rains and rainstorms, also put you in danger of getting caught in heavy currents or a flood.
  • Don’t go near the river bank or into the water when alone. Go in groups or don’t go at all. Suppose you are with a group of informed people prepared for the dangers of the river. In that case, multiple people can help in an emergency. Remember, it’s not recommended to get into the Mississippi River for swimming or in small boats.
  • Be aware of your surroundings and take caution if you see any animals in the water. Alligators, snakes, snapping turtles, and bull sharks could be lurking. Generally, these animals don’t attack unless they feel threatened, but you might accidentally agitate one that reacts defensively.
  • Enjoy river activities by letting experienced professionals take good care of you. Instead of swimming or kayaking in the river, enjoy a riverboat cruise steered by licensed captains who know the river well. Hike and camp in safe areas along the river, always staying at least 10 feet back from the bank.

There are many ways to enjoy activities on or near the water without high risks to your safety.

It’s an Iconic River that Requires Respect.

The Mississippi River is one of the most iconic rivers in the United States. But, unfortunately, it is also one of the most dangerous. Respecting this fast river’s power and risks is essential to your safety and the safety of others.

Many factors make the river dangerous, including currents, floods, wildlife, and pollution. And there are far too many accidents and drownings every year because people don’t realize the dangers or prepare for emergencies.

Before visiting the Mississippi River, it is vital to learn about the dangers and take precautions to stay safe.

The photo featured at the top of this post is © iStock.com/Willard

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About the Author

Jennifer Haase is a writer at A-Z Animals where her primary focus is on plants, pets, and places of interest. Jennifer has been writing professionally about plants and animals for over 14 years. A resident of Nebraska, Jennifer enjoys gardening, floral design, nutrition studies, and being a cat mama.

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