Caving In

The limestone monolith towered above Shasta Lake within the Trinity Alps National Forest. Naturally carved within its mighty limestone crags was one of the biggest cave systems in the U.S.

We boarded a small boat and easily motored across to the other side of shimmering Shasta Lake. A solitary bald eagle roosted atop a gnarled snag. Other than Alaska, Shasta Lake has the highest concentration of bald eagles in the U.S.

From below the limestone cathedral, we hopped on an old bus that drove us up a precariously steep dirt road to the visitor center and the entrance of the cave. The cave complex was 900 feet above Shasta Lake.

Shasta Shade

Inside the eight chambers, geological formations continue to evolve due to water. The caverns are dated to at least 200 million years old. The caverns are a showcase of natural wonders where a variety of limestone formations like stalactites, stalagmites, columns, and flow stones were on display. Limestone is one of the most prominent carbonate rocks found inside caverns.

Native Americans used the main chamber for ceremonies, specifically the Wintu tribe. J.A. Richardson was the first white man to find the cave in 1878. His name was scrawled on one of the gritty cave walls during his exploration of the grotto.

“Cave Dave,” who has lived and worked in and around the Shasta Caves for most of his life, is an expert in probing deep inside the region’s myriad of girthy grottos. There are three known caverns in Shasta County, but according to “Cave Dave” there are others hidden throughout the forest.

“There are lots of other caves in the region,” he said. “We’re not revealing their whereabouts due to safety
concerns.”

Just on the other side of the visitor center, a burly steel door was the entry point into the cavern. Our guide, Nicole, led us through a maze inside the steep, winding grotto. One of the visitors asked her, “what if there was an earthquake?”

“If there was a quake you wouldn’t feel it in the cave,” she said. “It’s the safest place to be.”

She was spot on. Little did we know, and literally as Nicole spoke, McKinleyville on the north coast between Arcata and Eureka was experiencing a sizable seismic shift. A 7.0 quake caused lots of structural damage along the coast. Immediately, a tsunami warning went into effect from the Oregon border down to Santa Cruz, CA. Fortunately, no great wave reached that rugged part of the coast.

Inside the dark, low-lit, dank cave we didn’t see or feel a thing resembling a quake. The ground beneath our feet was muddy, but solid.

Free Flowing

But it does “rain” inside sections of the cavern. After heavy rainfall like the recent “Bomb Cyclone” that hammered Northern California in late November 2024, the cave doesn’t allow escape from the wet. Reports of six inches of rain per day hit Shasta Lake and the Sacramento River. Limestone is naturally filtering rock, and in several of the narrow corridors and chambers it was still seeping through from above. There were still lots of puddles and mud throughout the cavern. After two wet winters, Shasta Cavern was described to us as if there were torrential downpours requiring rain gear inside the cave.

However, the sound of dripping water inside was a soothing natural acoustic, drifting along the path that requires visitors to climb and descend 600 steps.

The last big, significant room had the best light with a high ceiling. Little brown bats were concealed in the upper reaches of the ceiling. They hibernate there during the winter and are seldom seen. Other cave dwellers included salamanders living in a lower room and several insects surviving inside as well.

After an hour of meandering through the cave, we opened the steel door, where our eyes adjusted to the bright sun and stellar views of Shasta Lake. The dark depths of the grotto were in our wake, but there’s a whole subterranean life waiting to be explored in the Trinity Alps.