Why the Mississippi River once flowed backward for three days

During the winter of 1811–1812, people living near the Mississippi River saw something they probably thought they’d never witness. It was the river pushing the wrong way. Yes, rather than flowing south, the current surged north for a short while. What caused it to do this, and could it happen again? That’s what we’re going to find out.

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The earthquakes that set it off

The trouble started late at night on December 16, 1811, when a huge earthquake hit the New Madrid region of Missouri, shaking an area bigger than most states. Two more followed in January & early February. However, these weren’t small tremors you might sleep through. They were actually so strong that even places far to the east felt them rumble through the ground.

Where on the river it happened

The February quake struck the area from New Madrid up to a bend near Kentucky. That stretch sits right on top of a fault that cuts across the riverbed, with the bend jerking upward in some spots & dropping in others. Such a sudden shift happened exactly where the river flowed. As such, the water reacted in a rather dramatic way.

What can make a great river run upstream

Earthquakes can throw big chunks of land upward in just a few seconds. When that happens under a river, the water slams into the new “wall” of land, and in the case of the Mississippi, parts of the riverbed went up so quickly that the current reversed. There were also powerful wave surges that raced back upstream.

How long the upstream surge lasted

The old reports talk about the river “running backward.” However, they don’t mean it flipped directions for days on end, as the backward flow only lasted a little while each time the quakes hit. It didn’t reverse continuously for three days. Rather, the region shook over & over for months, so different towns experienced different moments of the river acting strangely.

Why “three days” became part of the story

So where did the “three days” idea come from? It’s because people told & retold the story over time, with those separate events eventually sounding like one big, drawn-out episode. Yes, it flowed backwards, but it was for a short while, and not three days straight.

What else changed on and around the river

However, the quakes messed with more than the water’s direction. They also changed the landscape, as fault movement created sudden drops in the ground, which trapped streams. This turned parts of northwest Tennessee into what became Reelfoot Lake. Riverbanks also slumped into the water, and some areas along the river even had temporary waterfalls.

How researchers pieced it together

Nobody had seismographs back then, and it took a while for scientists to figure out what happened. It was only years later that they managed to use geological evidence & reports to trace where the faults run under the river. They then matched these with descriptions from people who lived through the shaking.

The following sources were consulted in the preparation of this article: