How I Spent My Summer--Travelogue: Part IV

Trip #4--Lava Tubes

My son-in-law, Nick enjoys exploring and caving.  No matter where he goes, he always finds cool stuff to do.  Then he shares it with the rest of us.  When his friend, John came to visit last month, Nick took John and I and my older sons, Tyler and Haydn out in the Idaho desert to go exploring.

The Idaho desert north of our town was created by lava flows on top of lava flows.  In some canyons, there are up to seven separate lava flows visible.  When lava flows, sometimes it flows into a channel and when it does, the sides and the top of the flow cool faster than the middle, so a hard shell is created.  That shell can be thirty or forty feet thick, or more.  Eventually, the molten lava flows out and all that is left is a hollow tube.  Thousands of years later, sometimes a side will collapse and expose the tube.  Sometimes conditions are just right and ice will form in the tube and there will be ice year round.  They call them, Ice Caves.

Sometimes animals used them for their dens, early Americans used them for shelter and there is evidence that some native peoples have used the ice caves for preservation of food.  During the Cold War, part of the defensive strategy of the United States was to use some of these natural caves to shelter local populations in the event of a nuclear strike.  We have one such cave in the desert here.  They were called the Civil Defense Caves and during the Cold War they were stocked with food and water and supplies.  They were supposed to shelter 8000 people.

While we were in the desert, we spelunked three caves.  The first was the ice cave, the second was a lava tube with no ice and the third was the Civil Defense Caves.

Cave #1-The Ice Cave
This cave has Ice year round.  To get back into it there is a slide worn into the ice from so many people climbing in it year after year.  There are a couple of large chambers and areas where the roof has collapsed so the tunnel is narrow.  At the end of the main tube there is a frozen waterfall.  Above the main tube is another tube that also has ice in it.  We spelunked in both of them.




Rock formations such as this indicate the presence of a collapsed lava tube



Nick, Tyler, Haydn and John getting to the Ice Cave

The Ice cave lava tube has several areas where the ceiling caved in.  To get to the cave you have to climb through several of these areas.




The entrance to the Ice Cave

The ice begins within the first fifteen feet underground in the ice cave.  The main tube has a rope embedded in the ice that you can use to aid yourself down into the main chamber.  After that you have to navigate around a huge ice dam to get into the rest of the cave.  This involves laying on your back and kicking off the ceiling to propel yourselve through the tube.




John at the ice slide

To get to the upper chamber you have to do a little rock climbing with toe holds and finger holds.  It isn't too tough, but one false move and it could be catastrophic.  When you get into the tube, however, the ice crystals on the ceiling are very beautiful.



Ice crystals on the ceiling



Haydn, Tyler and me at the end of the upper cave



The view, emerging from the Ice Cave

Cave #2--The Lava Tube
Nick has lava tube radar, so he set out across the desert for a hundred yards or so and found another lava tube.  This one was much more pristine than the Ice Cave.  This lava tube wasn't collapsed as much as the Ice Cave, so it was long and round.  Almost perfectly so.  We were able to cave in this one for about a quarter mile before it became impassible.  It was very cool inside.



Nick at the entrance of the second cave.

Inside the second cave.

Haydn, Nick and Tyler inside the perfectly round tube.

Cave #3--The Civil Defense Caves
The Civil Defense Caves are about fourteen miles outside of Rexburg, Idaho on the desert.  Nowadays they aren't full of supplies or water, but they are a destination for history buffs, geologists and spelunkers.  I had been here once before, when I was a teenager, but I didn't have a flashlight and stayed in the opening, didn't venture any deeper than the existing light would allow.  I also think I was on a field trip and the teacher wouldn't let us go very far into the caves.



Dirt road from here

Entrance to the Civil Defense Cave

Inside, looking out.

Haydn and John inside cave to show scale

The Civil Defense Caves are two ends of a massive lava tube.  The ceiling in most places was forty to fifty feet high.  The only places it wasn't were the areas where the ceiling had collapsed and there was rubble on the floor.  The main cave is 3000 feet long and about twenty yards wide.  This is a large lava tube and it was the government's idea for surviving a nuclear attack.  Gives new meaning to the term, "Bomb them back to the stone age."