Where Spelunkers Go Ape -- Beneath Our Most Restless Volcano, Ape Cave Gives An Eerie Peek Into The Belly Of The Beast

Like most Northwesterners, I vividly remember May 18, 1980 - the day Mount St. Helens exploded.

We stood in the front yard and watched giant, slate-colored clouds, containing millions of tons of ash and volcanic rock, engulf the sky.

Folks were talking as if it were the end of the world.

It's been almost 20 years, but each time I see the 8,366-foot, smoky-gray mountain, those memories erupt stronger than ever.

The 1980 blast caused massive damage to the northern slope of St. Helens. But this Southwestern Washington mountain, the most active of Cascade volcanoes, has deep scars on all sides. It has erupted 14 times in the past 4,000 years.

On the south side of the mountain, covered by rocks, grass, dirt, ash and leafy alder trees, remnants of ancient lava flows can be explored. Ape Cave, a 2.5-mile lava tube that was created about 1,900 years ago, is one of the most popular attractions. It was formed over the course of a year when St. Helens' billowy pahoehoe (pronounced "pa-HOE-ee-hoe-ee") basalt began to cool, crusting over with a thick, insulating shell.

Once the eruption ceased, lava drained from the resulting tubes and left a large passage that's similar to a mining shaft or railroad tunnel. In some areas, the cave is 30- to 40-feet tall. In others, it's about six feet high.

Ape Cave was discovered in 1946 by logger Lawrence Johnson. Despite its name, there aren't any resident primates; it was named after the Mount St. Helens Apes, a local outdoors club that explored the lava tube during the 1950s.

(Its name, and local lore, have led to speculation that Bigfoot may have once lived there, but there have been no sasquatch sightings lately.)

During a recent visit, our first stop was at Ape's Headquarters, just outside the cave entrance, where you can rent lanterns, or buy postcards, souvenir books and hiking guides. Operated by the Northwest Natural History Association, the shop is scheduled to close for the season at the end of this month unless there's enough funding to keep it open during October.

Ape's Headquarters also offers hour-long guided tours of the tube, but we opted to venture on our own. With Coleman lanterns in hand, we slowly climbed down the stone steps and 18-foot metal stairway into the mouth of the cave.

"Wow! This is scary!" my companion exclaimed. Nervously, I agreed.

But as our eyes adjusted to the darkness, it didn't seem as spooky. In fact, the feeling of not knowing what was around each corner made it even more fun.

Warm layers of clothing are definitely recommended: The cave stays around 42 degrees Fahrenheit year-round. Several areas are quite drafty, with winds up to 7 miles per hour, experts say. You'll want to wear a hat, too, because water occasionally drips from the ceiling.

With a floor the texture of sandpaper, and some rock debris to climb over, the 4,000-foot-long lower section is easy to complete. The 7,000-foot upper section of the cave is not recommended for novice spelunkers because its floor is covered with rubble.

Bats can sometimes be found in Ape Cave, but usually only at night when they are foraging, said Jim Nieland, a cave management specialist for the Mount St. Helens National Volcanic Monument.

If you're lucky, he said, you'll see a grylloblattid, a large cockroach-cricket-type of insect that uses a natural antifreeze to withstand cold conditions that kill, or paralyze, most bugs.

"They're thought to be a relic from the ice age," he added. "They were once thought to be the rarest insect in the world." (Thankfully, we didn't see any of the ice-age bugs or other residents, such as deer mice and spiders. The echo from our screams probably would've caused seismic activity . . . )

We each used a bright lantern and a flashlight to view the cave's features. There's a dark, shiny glaze on some parts of the cave where hot gases melted the wall surfaces. In some places, the glaze slumped while still molten, forming ripples.

Though geology was my least favorite college course, I liked studying the loose, volcanic rocks. Some of them looked like sponges and coral, covered with tiny holes. Others had a shiny, scalloped pattern, as if somebody carved them with a melon-ball scoop.

We used flashlights to follow the cave's deep, vertical contraction cracks, which occurred when the 2,000-degree lava was cooling. The walls might not appear sturdy, but Nieland said there's no need to worry - none of the cave's collapses have occurred in recent times, not even during the 1980 eruption. (Monument officials add that higher levels of seismic activity reported earlier this year should not discourage visitors. The shallow quakes were on St. Helens' lava dome, about seven miles north of Ape Cave.)

In some areas, where the smooth wall lining has fallen away, you can see bumpy, hardened soil that was baked brick-red from the heat of the lava.

About a half-mile in, you'll find the cave's most famous feature: the Lava Ball (also called the Meatball), where a 3 1/2-foot-wide chunk of solidified lava was wedged into a portion of the passage. And while you're exploring, don't forget to look up at the ceiling, where several thick vein-like formations snake through the top of the cave. (They look like something out of the movie "Tremors.")

"It's amazing to be down here and wonder how it formed," said Kellie Stuczynski of Camas, Clark County, who visited the cave recently. "It's big and open, so even though I'm a little claustrophobic it's not that bad."

The return trip proved to be just as interesting. We saw several cracks and large rocks that we hadn't seen earlier.

After returning the lanterns, we took a walk through the nearby Trail of Two Forests, a quarter-mile barrier-free boardwalk winding through the remains of an old-growth forest that was engulfed by the lava streams that ran through Ape Cave. As the molten rock oozed through the area, it caused trees to break off and topple onto the forest floor. The lava slowly hardened as the trees burned away. Perfect casts called tree molds remained.

Most of the remnants of the ancient forest have been covered by plush moss and the area's new, emerald forest - a hopeful sign that the moonscape scars on the north side of Mount St. Helens will heal with as much grace and beauty. ------------------------------- If you go:

-- Ape Cave and the Trail of Two Forests are about 15 miles east of the town of Cougar, Cowlitz County, in the Gifford Pinchot National Forest, in Southwestern Washington.

From Interstate 5, take Exit 21 (Woodland exit) and go east on Highway 503. Continue about 30 miles, through Cougar. The road becomes Forest Road 90 near the Swift Reservoir. Continue to Forest Road 83, and turn left. From there, signs will direct you to both recreation areas. Information: Mount St. Helens National Volcanic Monument headquarters, 360-247-3900.

-- Ape's Headquarters is open daily from 10 a.m. to 5 p.m. at the trailhead for Ape Cave. It's expected to stay open through the end of the month. Lanterns can be rented there for $2 a day, and must be returned by 5 p.m.

-- Mount St. Helens National Volcanic Monument headquarters is three miles north of Amboy, Clark County, on Highway 503. It provides guide books, maps and information on road conditions.

-- Monument Passes, which can be purchased at Ape's Headquarters or the monument headquarters, are required to visit Ape Cave. Cost is $8 for adults, $4 for senior citizens. There is no charge for children younger than 15. The pass is good for three days. It can also be used at other sites in Mount St. Helens National Volcanic Monument.

-- Wear warm clothes, a hat and sturdy shoes. If you plan on hiking the entire cave, allow three hours. Free brochures on the cave are available at monument headquarters and Ape's Headquarters.