Inside and Out Old Station's Lava Tube: The Subway Cave

July 21, 2018, The Subway Cave

Date: May 14, July 7, and July 21, 2018
Place: The Subway Cave, Old Station, California
Coordinates: 40.685296, -121.418771
Length: about 1/2 a mile, the complete loop.
Level: Easy. Flashlights needed.

We discovered the Subway Cave seven years ago while on a big California road trip with friends. Although we didn't plan it, we arrived there in perfect timing to join a group tour guided by a ranger of the Lassen National Forest. We have visited lava tube caves before, and the Subway Cave is a very impressive lava tube. It is fascinating any visit but especially so when learning about it from an expert guide. Since then I never miss any opportunity to take people down that cave whenever we're in the area north of Lassen Volcanic National Park.
In the past few month I had the opportunity to visit there four times, and on the last three I even remembered to take my camera along :-) On our first visit of the cave in 2011 we didn't take the camera and I posted cave photos that were taken by our friends, and had no outside photos at all. This time I include photos of my last three visits there. Each photo has the date taken in its caption.

On July 7 I was there with my family, including Grandma Quail and Pappa Quail's 15 years old nephew. It was a beautiful, warm day, and all all of us were excited about going underground, even the chikas who had been there numerous times already. In fact, they did much of the guiding themselves, sparing me the need to explain every phenomenon. 

July 7, 2018, The trailhead

Two months earlier, on May 14, I was there with my botanist friend Anenet. She had visited Lassen Volcanic NP before but at that time we didn't know about this cave and so missed seeing it. My friend was interested mainly in wildflowers, and although it was fairly early in the season for that area, we did see some bloom outside the cave. 

May 14, 2018, Common Manzanita, Arctostaphylos manzanita

Some of the wildflowers were very exciting, like the peony which bloomed just by the trailhead.

 May 14, 2018, Peony, Peonia brownii

My latest visit to the Subway Cave was on July 21 with a group of families I was taking to Lassen Volcanic NP. By then of course, everything that was blooming in May had fruits. 

July 21, 2018, Common Manzanita, Arctostaphylos manzanita

It's a short walk from the parking lot to the cave entrance. There's a short flight of stairs going up to where the view opens up and you're in an open chaparral of manzanita and mountain mahogany on dark volcanic soil. There's a feeling there of complete wilderness although the site is so close to the town of Old Station. 

July 21, 2018, Left: the cave entrance. Right - the return trail

A few yards further there is another flight of stairs that leads don to the cave. On Many occasions I have tried photographing the features of the cave but only very few of my photos came out right. At the top of this post - the opening of the cave. Seeing it explains its name - it is so perfectly round and smooth, and it's so large, one gets the feeling that the train will be coming though at any moment.
Lava tubes are formed when the outside of a liquid lava flow cools down and solidifies while inside it remains hit and liquid, flowing through until the source volcano stops spewing and a tunnel is formed. Lava tubes are quite common in volcanic fields. The first one I've seen was in Hawai'i, and we've also explored some of the caves in California's Lava Beds National Monument, but the Subway Cave is by far my favorite. I never get tired of going there.
In the photo below - the solidified lava 'stalactites' that formed as the cooling lava dripped from the ceiling. Some of these are actually real stalactites, sedimented by rainwater. Very small still, because they are very young (in geological terms) - the Subway Cave is only 20,00 years old.

July 21, 2018, Ceiling Lava Drops

Some years ago a strong earthquake shook the area and broke a fissure inside the cave. This fissure runs across the floor and the sides of the cave and is easy to find when you look for it. 

July 7, 2018, The Big Earthquake Crack

The hot lave was bubbling with gasses. One of these bubbles solidified as it popped, immortalizing that geological moment.

July 21, 2018, Lava Bubble frozen in time. 

The cave is very convenient to walk through. The floor is not smooth - solidified ebbs and eddies echo the past lava flow - but it is level. The ceiling is high and there are only a couple of places where a tall person might need to stoop a bit. In winter and spring the cave floor can be wet or somewhat flooded so proper footwear is required.
There is a flight of stairs at the other end of the cave as well. After getting used to the daylight again it is good to look back at the cave's opening. Lava tubes are discovered in places where they collapse and the underground hole is expose. The Subway Cave tube extends beyond the public accessible part, but the extension is a bat sanctuary and shouldn't be entered.

May 14, 2018, Wide Currant, Ribes sp. at the cave's south opening.

Outside the south opening of the tube (the one farthest of the parking lot) the trail looks as if it goes on strait. It does - but to the town of Old Station. To get back to the parking lot one needs to turn right immediately after exiting the tube. But I do recommend taking in the wonderful view southward before turning back. Between the trees peeks Lassen Peak. 

July 21, 2018, Southward View

The Subway Cave is about 1/4 mile long. The trail above ground as only slightly longer as it meanders through the chaparral. Between and below the shrubs and bushes grow little herbaceous plants that split among them the bloom season. Early in spring  there were the peony and tiny tarweed plants.

May 14, Opposite-leaved Tarweed, Hemizonella minima

Later in the season the monkeyflowers were blooming. Several little species can be seen in that region.

July 7, 2018, Monkeyflower, Diplacus torreyi

Recently the genus name for these was changed from Mimulus to Diplacus. Knowing the names is cool but they are pretty, regardless of the names people give them.

July 7, 2018, Monkeyflower, Diplacus mephiticus 

Another common shrub in that place is the mountain mahogany. It goes best right above the lava tubes, its roots often penetrate the tube ceiling and enjoy the cool, moist air inside. In fact, one can often tell the outline of a lava tube by the line s of mountain mahogany above ground. On my spring visit I saw the mountain mahogany in bloom. It was nearly done already - I caught the tail of it.

May 14, 2018, Mountainmahogany, Cercocarpus ledifolius

Less than two months later the mountain mahogany bushes were covered with the delicate, feathery fruit.

July 7, 2018, Mountainmahogany, Cercocarpus ledifolius

It's neat to look and the pretty fruit up close but it is the entire bush in fruit effect that is truly striking.   It looks celestial, like a bit of cloud gone down to Earth.

July 7, 2018, Mountainmahogany, Cercocarpus ledifolius

The manzanita and mountain mahogany are the most common members of the chaparral community near the Subway Cave, but there are other shrubs there as well. They too, were nice to see in bloom.

Snowbrush, Ceanothus velutinus

The early bloomers really make a difference in the otherwise gray scenery of still wintering bushes.

May 14, 2018

It is a short trail back to the parking lot, but it is dense with beautiful nature sights and encounters. In the summer time the lizards are active and very easy to see when sunbathing out on the rocks.

July 7, 2018

Not always do they stay put for a photo but there are so many of them were that some do make it on pixels.

July 7, 2018

Going down the flight of stairs to the parking lot I got to see wildflowers that I missed while going up. Some I would probably have never looked at twice if not for the inspiration my botanist friend gave me on the previous visit. As it turned out, this one was a new for me species of penstemon - a genus I'm always happy to see out in the wild.

July 7, 2018, Rock Penstemon, Penstemon deustus

Going outdoors with children is a special treat because they always see things that I would otherwise miss. Like this pretty spider that my chikas and their cousin found hanging on the manzanita shrubs. 

July 7, 2018

The Subway Cave trail is small but very rich. A celebration of fantastic geology and complex community of plants and animals. Once discovered - this place has become a top pilgrimage site for me. I think I've mentioned that in the beginning of the post, I never miss an opportunity to go there whenever I'm around that area.

July 7, 2018 Small leaved Horsemint, Agastache parvifolia near the parking lot. 

Many thanks to members of the California Native Plants Society for their help in identifying plants!