Mysterious Pennsylvania Ice Mine Only Produces Ice in the Summer

The ice mine is open to the public again after a 25-year break. Original Curt Teich Postcard Donation/University of Illinois/Wikimedia Commons

Most people like to escape the summer heat with a trip to the beach or a swim in the local pool, but here's an alternative for those of you with more eclectic travel tastes: Coudersport Ice Mine.

The mine was a tucked-away roadside attraction in Pennsylvania's Appalachian Mountains for many years until it was abruptly closed down a quarter of a century ago. But now, after a 25-year hiatus, this hidden summer getaway is once again open to the public, reports Living on Earth.

The frigid cavern isn't just a great place to escape the summer heat; it's also something of an unsolved anomaly. Strangely, the cave only produces ice in the summertime, and it tends to produce more ice the higher the surrounding temperature gets. When winter falls and snow covers the hilltops, the ice in the cave melts. The phenomenon is so mysterious that some locals even claim (falsely) that the cave is manmade.

Originally discovered in 1894, the mine was first used to store meat and for ice harvesting. By the early 1900s, however, it was transformed into a tourist attraction. Inside the cave in the summer it gets cold, like walking into a refrigerator. It's as if winter hibernates here, waiting out the season until it can reemerge. The cave is about 40 feet deep, 8 feet wide, and 10 feet long. The ice that forms on its walls, often in the form of icicles, is generally clear and sparkling.

Though the anti-intuitive seasonal ice anomaly remains largely mysterious, there are theories. Experts say that cold winter air slips into the mountain through cracks in the rock formations, and due to the unusual interconnection of the crevices here, that cold air gets concentrated into chambers such as this one. The reason ice only forms in the summer is because of the seasonal humidity increase in the surrounding atmosphere, along with an increase in percolating groundwater, which becomes exposed to the freezing air. This strange pattern reverses itself in the winter, as warm air trapped in the rocks from the preceding summer escapes and melts the ice.

Part of the charm of the Coudersport Ice Mine, though, is that it retains much of its mystery. Perhaps it's best to simply think of it as a long-lost hole in the mountain where Old Man Winter sleeps.

At any rate, it's a great place to escape the sultriness of summer.