At the Devil’s Kettle Falls, the Brule river forks into two. While one part of the river flows normally down to Lake Superior, the other part just vanishes into a deep pit. Now scientists believe they have solved the mystery. 

The Devil’s Kettle Falls is an unusual waterfall located in the Judge C. R. Magney State Park. The falls has a giant, deep hole that swallows half of the Brule River, and, until recently, no one had any idea where that half ended up.

The Brule River flows through the Judge C. R. Magney State Park located in Minnesota. It makes a drop of 800 feet in a span of 8 miles creating several waterfalls. Among them lies the mysterious Devil’s Kettle Falls.

About one and a half mile from the Lake Superior, the river forks into two streams at the Devil’s Kettle due to the presence of a protruding rhyolite. While the right part of the river flows down normally and joins the Lake Superior, the left part of the river falls into a giant pit. You can see the pit in the image above.

Now logically, since the water needs to keep flowing, it has to come out somewhere. But for years, people have failed to figure out where exactly the water goes after it falls into the pit — that is until recently.

Over the years, researchers and many curious locals have poured items such as ping pong balls, tree logs, and apparently even a car into the hole and monitored the lake for the objects to emerge. So far, none of the objects have resurfaced.

Thomas Hobbes rightly said that curiosity is the lust of the mind. People were so curious to find out where the river ends up that they have conducted numerous experiments. One of the most famous experiments included the pouring of numerous ping pong balls into the pit. A phone number was etched onto each ball with a message that if found, the person should call back and would get a reward. Not a single call came to claim the reward.

Other experiments involved the throwing of GPS trackers, logs, loose change, and twigs. Local legends also suggest that people have been known to throw televisions, refrigerators, and even a car into the hole. But the probability of bringing a car to the crest of the waterfall seems highly unlikely.

Many theories have come up to explain the mystery. Some believe that there might exist an underground river. Others believe in the existence of an ancient lava tube that carries the water directly to the floor of Lake Superior. Both theories have been dismissed.

The theory for the existence of underground river was dismissed by geologists because such geological formations take place in soft rock types, like limestone. The area around the Devil’s Kettle is built of much harder rock.

Moreover, the existence of a lava tube deep down the falls is unlikely because, in the hundreds of the exposed basalt beds formed by volcanic eruptions in Minnesota, no lava tubes were ever discovered.

In February 2017, the Minnesota Department of Natural Resources finally established that the disappearing water resurfaces in the stream below the waterfall.

Finally, in February 2017, some light was shed into the mystery behind this unique waterfall. A team of hydrologists from the Minnesota Department of Natural Resources measured the flow rate of the water above Devil’s Kettle at 123 cubic feet per second. The water was flowing at 121 cubic feet per second hundreds of feet below the waterfall.

According to hydrologist Jeff Green, these rates are essentially the same and therefore, there is no loss of water below the kettle. This means that water is resurging in the stream from below.

To confirm their theory, researchers were planning to conduct a dye test wherein they would pour vegetable dye into the pit and monitor where the water resurfaces. But the researchers never came back as “there was not a significant scientific reason,” according to the park’s manager, Pete Mott.

As to the items that have disappeared when thrown into the pit, Green explains that due to the powerful recirculating currents, the items may have been disintegrated or held underwater until they resurface downstream at some time.
[source: 1, 2, 3, 4]