Lost Lake gets lost down a lava tube about six feet wide in this video shot by the Bend Bulletin.

In the mountains of Oregon — about two hours southeast of Portland — is a mysterious lake. Though a relative pond compared with the Great Lakes of the Midwest, Native Americans called this place “Kwoneksamach,” or “unknown.” After the first European Americans to document their first visit in the 1870s had trouble finding their way, the body of water ended up with a name worthy of Samuel Taylor Coleridge poem or a “Friday the 13th” sequel: “Lost Lake.”

But what’s most mysterious about Lost Lake is that, once a year, it actually gets lost. The lake drains through a hole and disappears.

“It fills up in the winter, when input exceeds the rate of draining, and then it goes dry and it’s a meadow,” Jude McHugh, spokesman for the Willamette National Forest, told the Bend Bulletin.

Wherefore comes this hole? It’s a lava tube, formed during a volcanic eruption when the surface of a lava flow cools, but hotter lava flows beneath the surface. Once the lava flows out, it can leave a tunnel. Here’s an explanation courtesy the U.S. Geological Survey:

Lost Lake is emptied in the winter when the snowpack of Oregon’s mountains freezes, depriving the lake of its inflow. In the summer when the snow melts, it fills back up again. This is exactly what is not happening in drought-ridden California and other Western states, where lakes such as Lake Mead and Lake McClure are at fractions of their capacity.

Where does the water go once down the tube? No one knows, but it may seep into a giant aquifer beneath the surface of the Cascade Mountains, replenishing groundwater. And though Oregon had a relatively low-snow winter and some counties are facing drought, Linn County, where Lost Lake is located, is not in danger.

Still, the Bulletin reported that some local wits have attempted to defy geology, plugging the hole with car parts and debris. Do not fear: They will not succeed.

“If anyone was ever successful at plugging it — which we’re not sure they could do — it would just result in the lake flooding,” McHugh said.

Though mysterious and romantic, Lost Lake is not the only body of water in Oregon lost and found again as the seasons turn, turn, turn. Fish Lake is emptied by a lava tube as well — but who wants to go there?

Correction: An earlier version of this post incorrectly identified the location and size of Lost Lake, and the location of Lake Mead.