History Corner - In Search of Lava Tubes

I have heard stories about the lava tubes of Elmore County. Desperados would drive their stolen cattle into a cave and come out miles away, near the Snake River and far from the ranchers searching for them. Boy Scout troops would gather for movie night deep underground, enjoying scary movies in the eerie darkness.

Of course, notable caves surround us in Kuna, Gooding, Shoshone and Craters of the Moon National Monument. I wondered how Elmore County stacked up in this department.

“Concentrations of known lava caves are near Mountain Home,” writes Sylvia H. Ross in her booklet Introduction to Idaho Caves and Caving (Idaho Bureau of Mines and Geology, May 1969). “Most of Idaho’s lava caves are in the area of the Snake River Plain,” she asserts.

So I went looking for them, but they did not easily give up their secrets

Just what is a lava tube? Ross describes them as “formed by gentle, river-like flows of hot, ropy lava. As the flow extends itself farther and farther from the source, the outside of the flow has a tendency to cool and harden, leaving a crust or shell.” They are “by far the most common type of cave.”

In the area of our local Crater Rings National Natural Landmark are several known caves.

The best known of these is called “Smith’s Crack,” subject of several online videos and host to several Boy Scout outings. But my research showed these to be fracture caves, not lava tubes.

My first attempt at going underground was a visit to Eureka Cave, which is off Hot Creek Road southeast of the Mountain Home reservoir. This lava tube goes all the way to Glenn’s Ferry, I’m told.

This “cave” is now just a pit full of rocks, graffiti and trash. My extension ladder just reached the bottom of the pit. I found it would take mammoth effort to clear the black lava rock debris to access any lava tube that may be behind it. So I climbed back up with a couple of bags of garbage, unable to visit any tunnel.

I was told that the Bureau of Land Management dynamited this tunnel years ago to keep people out. Well, that was a story I wanted to hear, so I wrote them. Dave Draheim, Outdoor Recreation Planner for the Boise BLM, told me it was not so. It is not even on BLM land, but rather state land.

Did Idaho bring the tunnel down? Sharla Arledge, Public Information Officer for Idaho Department of Lands, would not own up to it: “I am afraid we are not a big help. I have not been able to find a member of staff that has information or history on the Eureka or any other possible caves or tubes. We believe it was a natural collapse of the roof of the lava tube.”

Next up was Higby Cave, described by Ross as a 1,100-foot-long lava tube between Boise and Mountain Home. She also adds the tempting rumor that “gold from several holdups in the late 1880’s is buried in the cave.” As if I needed any more motivation to visit.

I did a Web search to find the exact location. Alas, I found that the BLM closed access to Higby years ago. Their Notice of Permanent Closure on Public Lands, dated 04/12/2010, makes note of “changes in the cave’s structural integrity and related potential hazards.” This provides an example of what the BLM does with hazardous caves: they closed off the entrance with a “bat-friendly” gate and blocked vehicle access with large rocks. That makes more sense than dynamite.

Clearly, I needed some help in accessing local lava tubes, so I contacted the Idaho caving club known as “Gem State Grotto.” Their Web page includes these enticing lines: “The vast lava fields making up the Snake River Plain contain hundreds of lava caves of all manner of size and shape. There are caves containing miles of lava tubes and lava caves containing complex mazes.”

Well, okay then. I’m not looking to visit hundreds of caves or walk miles of tubes. One short walk would do just fine, thanks.

For good reason, cavers keep their secrets pretty close to the vest. Caving can be dangerous, and people left to their own devices are notoriously bad at conserving resources (see Eureka Cave above).

A personal introduction and explanation was in order, so I attended their first post-Covid meeting in Boise on May 19. I told them I was not looking to harm their caves or myself. I hoped that once I explained my purpose, I might even score a guided tour from an experienced old hand.

That didn’t happen. I learned that the caves of most interest to the current Gem State Grotto were in Hells Canyon. The club seems to have lost a lot of knowledge of the lava tubes of Elmore County.

That’s not to say they were dismissive of my quest. Randy Vance (secretary treasurer) generously researched the prominent lava tube system in Prairie and provided a map.

Armed with this map and a couple of names of people to ask, I drove to Prairie with a friend, an experienced caver. There we found a long-time resident who was friendly and knowledgeable.

Since we were talking with an experienced cattle man, I tried the story about rustlers driving cattle through lava tubes. He was highly skeptical. Openings are generally small, the floors covered in unstable rocks, and cattle are highly averse to running into a dark tunnel.

In further conversation, he informed us that there is no public land in Prairie. Any lava tubes that may be in the area would be on private property with no trespassing allowed.

What I was left with was a basalt rock pit by the roadside that looks to these untrained eyes like a collapsed lava tube. Across the road is a possible open tube, but it is not accessible to the public.

So lava tubes are around. Getting into one is not easy.

The author acknowledges the kind assistance of the Bureau of Land Management, Idaho Department of Lands, Gem State Grotto, Deb Neeley, and David Cunningham, whose help made this article possible.