There's a giant hole that's draining a lake like it's a bathtub

Like something straight out of the Twilight Zone, a swirling vortex has opened up in a giant lake in Texas.

U.S. Army Corps of Engineers/YouTube

The gaping hole - which appeared recently in Texas' Lake Texoma - alarmed everyone from Twitter users to the Tulsa District US Army Corps of Engineers, who posted a YouTube video of the vortex. Below the video, they describe the hole as being "8 feet in diameter and capable of sucking in a full-sized boat."

U.S. Army Corps of Engineers/YouTube

But despite how crazy it looks, there's a perfectly normal explanation for the spooky hole:

The water is being drained.

"Just like in your house when you fill a bathtub full of water and [open] the drain, it will develop a vortex or whirlpool," BJ Parkey, assistant lake manager at Lake Texoma, told Business Insider.

One of the largest reservoirs in the United States, Lake Texoma lies on the border of Oklahoma and Texas, and is formed by the buildup of water at Denison Dam on the Red River. When the water levels get too high, as they have in recent weeks, the Army Corps opens sluices called floodgates at the bottom of the lake to drain the water into the river. The flowing water creates cyclonic action, much like a tornado, which is widest at the top and tapers down at its tip, said Parkey.

Could it really swallow a boat?

If the whirlpool is large enough, it would be easy for a boat to be caught up in it, Parkey said. To avert a watery disaster, the Army Corps has marked the area with buoys and signs to keep people away. He said the entire area is off-limits for boats.

The size of the vortex depends on a number of factors, including the lake's elevation and how wide the flood gates are opened. Although the video description says the hole was 8 feet wide, right now it's probably more like 2.5 to 3 feet, said Parkey.

The lake's vortex is rotating counterclockwise, which may lead some people to think is due to the "Coriolis effect" caused by the Earth's rotation. (This is the same logic some people have used to explain why toilets flush counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.) As the Earth spins, it causes winds in the Northern Hemisphere to bend to the right and winds in the Southern Hemisphere bend to the left. But the effect happens on a much larger scale than toilets, or even tornadoes. it usually comes into play with storms that are about three times larger than the ones that typically generate tornadoes.

The vortex is especially dramatic right now because of the deluge of rain the region has received over the past few weeks, which has caused massive flooding. Lake Texoma's waters reached a record-high elevation a few weeks ago of nearly 646 feet above sea level.