These are the days that fry men’s soles. It’s hot. But who needs an air conditioner in Central Oregon? It’s usually cold, right? But it’s hot today. And I’m guessing it will be again tomorrow. But who needs an air conditioner? It’s Central Oregon.

There are ways to beat the heat. Go swimming. Go walk around Costco. Go lie in front of the fan.

I’ve got a better idea. Go underground.

It’s 42 degrees inside Lava River Cave. Which makes the place a genuine point of interest in July and August. As strange as it may seem, you just might want to pack a sweater.

Besides being a refreshing alternative to the sweltering High Desert above, Lava River Cave is a great place to learn about the forces of vulcanism and subterranean habitats.

Outside the cave, for instance, it’s ponderosa pine and bitterbrush business as usual.

But right at the entrance, things are different. This small area, where the cool cave air blends with the warm air outside, is home to several moisture-loving plants such as false solomon’s seal, roses, raspberry, strawberry and wax currant, according to the Northwest Interpretive Association.

But first things first.

When you stop at the office not far from the parking lot and pay your $5 day use fee, it also makes sense to rent a lantern for $3. Because unless you brought some type of light source, you won’t be able to see inside the cave.

And there’s stuff worth seeing. Because you’re walking through a lava tube that once pulsed with fluid magma. The tube is a crusted-over channel. When the lava stopped flowing, the tube drained and created a cave.

Just inside, there’s a jumble of volcanic rocks that fell over time from the roof and sides, a disconcerting thought if you dwell on it for too long.

The tube is 5,200 feet long; in some places the ceiling is right above your head, in other places it’s more than 50 feet high.

Where there are no stairs, the footing can be a bit precarious, especially at the beginning. But most of the cave is fairly easy to negotiate. Somewhere along the line (about 1,500 feet in) the tube passes 80 feet under Highway 97.

A local trapper named Leander Dillman discovered the cave in 1889 while he was hunting. He used it as his private refrigerator to keep game fresh. For years the tube was known as Dillman’s Cave. But, according to the Interpretive Association, Dillman was convicted of a crime in 1921 and the cave was renamed.

Now part of the Newberry National Volcanic Monument, Lava River Cave is Oregon’s longest uncollapsed lava tube.

If you’re in a volcanic sort of mood and still up for some more exploring after experiencing the tube, the Lava Cast Forest is just a mile or so south down the highway (and several miles east). The 1-1/2-mile loop trail passes by an eerie 7,000-year-old lava flow that pulsed out of Newberry Volcano, covered the trees and then cooled. What’s left are ”molds” where the pines once stood.

Another interesting stop is the Lava Lands Visitor Center (back up Highway 97 toward Bend) where you can bone up on the geology and natural history of Central Oregon and see first hand where all the surrounding lava came from – Lava Butte.

Or you could beat feet to Costco, break down and buy an air conditioner. It’s hot out there.

Jim Witty can be reached at 541-617-7828 or jwitty@bendbulletin.com.

If you go:

Getting There: From Bend, drive about 12 miles south on Highway 97. The turnoff is on the left at a sign that says Lava River Cave.

Access: Hikers.

Permits: A Northwest Forest Pass is required.

Hours: The cave is open from mid-May to mid-September. Lanterns must be returned by 4 p.m.

Contact: 593-2421.