Natural Bridge

We parked at the head of the Natural Bridge Bike Trail and ate a picnic lunch in the car.

After lunch, we took the charming two-mile roundtrip stroll through the woods. The trail was flat and paved, more or less. I was delighted that Ma and I could enjoy it together.

The end of the trail promised a feature called a "natural bridge". It forms when a creek wears a hole through a rock and then shifts course to run through the opening.

So we get to the end of the trail, but where is the bridge? No sign of a creek either. Then we look up. Do you see it?

How 'bout now?

It's bigger than it looks. And higher. Do you see me (mid-photo, in pink) for comparison?

There are two trails leading to the bridge. One is a switchback trail that loops behind the bridge and crosses the creek (not using the natural bridge, but a different man-made bridge) and comes back down on the opposite side. The other trail goes right up the "gut" to the base of the bridge. That's the one I am climbing in the photo. The creek is clogged with logs and leaves. At the top, it's barely a trickle. Hard to believe a tiny stream could carve such a huge hole!

There were several other tourists wandering around at the base of the bridge. One of them claimed to see a "beaver" in the creek. I don't think it was a beaver. Instead, I think she saw one of these little guys: a yellow-bellied marmot. Add another check mark to our rapidly growing list of mammals.

West Thumb Geyser Basin

Yellowstone National Park sits on top of a giant volcano. The last time it blew its top was 600,000 years ago. The eruption left behind a 40-mile wide crater called a caldera. Over time, the lowest part of the caldera filled with water, forming Yellowstone Lake.

Hundreds of thousands of years later, pressure in the underground magma chamber found a weak spot in the earth's crust just to the west of the lake. The magma chamber "burped" and left behind a small caldera (a caldera within a caldera). The hole filled with water, uniting with Yellowstone Lake to form its "West Thumb".

The earth's crust is still thin here. Thermal activity abounds. Visitors are warned to stay on the boardwalks lest they scorch their feet on the hot ground.

Yellowstone is home to many different kinds of geothermal features. "Geothermal" means earth + heat. When you add water into the equation, you get a "hydrothermal" feature (water + heat). The classification of the feature depends on the amount of water, the chemicals in the water, and the feature's "plumbing".

Hot Spring: This is the most common hydrothermal feature in the park. Water gets heated underground and travels to the surface. It typically forms a pool at the surface.

Geyser: This feature is cyclical. The process starts with the accumulation of water in a chamber underground. The water gets heated. But unlike hot springs, it can't freely travel to the surface because the feature's plumbing has a constriction (like a nozzle on a garden hose). Pressure builds until the water flashes to steam and erupts out of the opening. Eventually, the pressure is relieved and the eruption stops. Groundwater re-accumulates and the cycle starts over.

Fumarole: If you remove the large supply of water from a hot spring, you're left with a steam vent called a fumarole.

Travertine Terraces: Sometimes the water in a hot spring contains high amounts of calcium carbonate (dissolved limestone). When the water hits the air, it loses carbon dioxide and can no longer hold onto its calcium carbonate (just like we learned in the caves a few days ago). The mineral gets deposited in a series of constantly shifting terraces.

Mudpots: Sometimes the water in a hot spring contains acid (often due to hydrogen sulfide being produced underground and percolating up through the water table). The acid breaks down the surrounding rock into clay. If there's enough water available, the clay becomes a mudpot. The surface of mudpots is frequently disturbed by bubbles of escaping gas.

Bacteria mat: When an area is constantly covered with warm water, colonies of microorganisms begin to form. These microorganisms are known collectively as "thermophiles". Examples include algae, bacteria, viruses, and fungi. The term "bacteria mat" refers to any thermophile, bacteria or not. Each species is adapted to live in a narrow temperature and pH spectrum. And each species exhibits a distinct color. So, we can use color to approximate the temperature of a hot spring and its runoff.

Different areas of the park are known for different features. West Thumb Geyser Basin has a few geysers and lots of hot springs.

This is the Abyss Pool. It's 53 feet deep.
The color tells us that archaea lives here. That means the pool's temperature is incredibly hot, about 199 degrees.

Note: at this elevation, water boils at approximately 200 degrees. So, that's why many pale blue hot springs are covered in steam.

This bacteria mat is gold and orange. So, assuming the pH is alkaline, we can approximate the temperature to be between 113-167 degrees.

(That's Yellowstone Lake in the background.)

Surging Spring

This pool is so hot that it actually boils in the middle. See the ripples?

Some of the thermal features are located in the lake itself.

This is Fishing Cone. Long ago, fishermen would reel in their catch, drop it into the boiling water of Fishing Cone, and pull out a fully cooked dinner.

Fishing Cone was also once a geyser. It quit erupting several decades ago and is now classified as a hot spring.

Remember those elk we almost hit earlier? Well, evidently they're part of a herd that frequents West Thumb Geyser Basin. The warm water attracts the mothers and their offspring.

The bad news for the elk is that the silica in the hot spring water wears away their teeth. But that's not a huge problem in Yellowstone. These elk are destined to be some wolf's or bear's dinner long before they die of old age.

The elk came in droves! I think Ma counted over two dozen.

Beautiful hot springs AND elk? How awesome is this!?

Apparently they didn't read the signs that said you'll get burned up if you leave the safety of the boardwalk.

Day 10: Back to Yellowstone

Today we return to Yellowstone.

It's tough to leave behind the majestic peaks of the Grand Tetons, but we have more sightseeing to do.

The Grand Tetons National Park is oriented north-south, with just two roads. It's very simple to navigate.

Yellowstone's central roads are laid out like a figure-eight, called the Grand Loop. (Actually, it's more like a loop wearing a belt across its middle.) Entrance roads branch off the Grand Loop to the south (Grand Tetons), east (Cody), north (Gardiner), west (West Yellowstone), and northeast (Cooke City).

Before we're through, we'll have traveled nearly every road in the park.

Our route today will take us up from the Grand Tetons, around the lower right curve of the figure-eight, to the point where the loop's belt pinches in.

*****
Our first stop today is Grant Village on the south entrance road. The Visitor Center here has an excellent display on the role fire plays in Yellowstone's ecosystem.

Until 1972, park rangers believed that fire was nothing but a destructive force that had to be stopped in order to preserve the natural environment. They could not have been more wrong. Fire performs a vital function in the circle of life. It enriches the soil. It maintains vegetation diversity. It kills off non-adapted (invasive) species.

The park is covered in lodgepole pine forests. Lodgepole pines produce two kinds of cones. One of them opens at a relatively low temperature, just 113 degrees. It mainly provides food for rodents. The other cone requires a thorough burn to open and become fertile. Lodgepole pine forests are characterized by tall trees and very little understory. A lack of understory means minimal fuel for a surface fire to spread. But as trees die off, they create fuel on the forest floor. It takes more than a hundred years' for dead trees to produce enough fuel for a fire to spread more than an acre or two.

Fire sweeps through lodgepole pine forests every 150-300 years.
It sweeps through grasslands every 25-60 years.

The last major fire to sweep through Yellowstone's lodgepole pine forests was in 1988. It burned 793,000 acres, or 36% of the park.

Our next stop was the West Thumb Geyser Basin. As we approached the turnoff, three elk jumped out of the woods in front of our car. What a rush!

But these elk were only the beginning...

Pilgrim Creek

We'd been hearing rumors all day of a "guaranteed moose" on Pilgrim Creek Road. We'd struck out seeing any wildlife in two of the park's major refuges: Willow Flat and Oxbow Bend. So, we were skeptical.

Pilgrim Creek did not disappoint.

Pilgrim Creek Road is a narrow, unpaved offshoot from the main road. Despite its location, they sure packed in the crowds to see this big guy. We parked among the sea of cars and walked through the treeline to a marshy area beyond.

And holy Toledo! There he was!

We watched him for about fifteen minutes. He pretty much stood in the same spot, devouring everything he possibly could. He was a massive eating machine. I was lucky to snap these photos of the few times he paused to lift his head.

The daylight was fading. It was time to head back to Jackson Lake and check in to our cabin for the night.

End Day 9.

Cunningham Cabin

The Grand Tetons National Park is very large, more than 480 square miles. But the entrance/exit gates don't match the actual boundaries. We'd been driving along the west road all morning, inside the gates. We reached the south end and exited the gates, but didn't exit the park.

At Moose Junction, we turned north and traveled the east road through the beautiful Jackson Hole prairie. You can travel the entire east side of the park without encountering an entrance gate at all.

As I mentioned earlier, there are several historical structures left from the homestead days. One of them is the Cunningham Cabin, pictured above.

John and Margaret Cunningham established the Bar Flying U Ranch here in the 1880s. The couple managed to remain profitable through drought and falling livestock prices, but they eventually succumbed in 1928. They sold out to the Snake River Land Company (the dummy corporation set up by John D. Rockefeller to unite Jackson Hole with Grand Tetons National Park).

Even more wildflowers

We were equally astonished by the flora in the Grand Tetons.

Ma and I spent many a moment wondering how so many wildflowers managed to thrive here. Is the soil/sun/climate really so well-suited that common weeds don't choke out the flowers? Is the ecosystem so perfectly balanced that rodents and birds don't eat the seeds before they sprout? It's unfathomable.

Vervain?

Wow, what is this??

These almost look like strawberry flowers.

No clue.

The foliage tells me that this is not a fleabane, an aster, nor a daisy. Therefore, I don't know what it is.

This is some kind of daisy.

Spirea?

Blue flax (Linum lewisii)

My suspicion is that this is a species of delphinium.

Western cone flower (Rudbeckia occidentalis).
Nope, it doesn't get petals on it. And it's almost as tall as I am.

Buckwheat

Lupine

Thickstem aster (Aster intregrifolius)

Prairie goldenrod (Solidago missouriensis)

Skyrocket gilia (Gilia aggregata)

more Skyrocket gilia (Gilia aggregata)

Mountain hollyhock (Iliamna rivularis)

With all those flowers around, there were plenty of butterflies, too.

Jenny Lake

The strangest coincidence happened when we parked at Jenny Lake. There were no picnic tables nearby so we decided to eat our picnic lunch in the car. While we were eating, several ladies returned to the car next to us. Amazingly, they were the same ladies we'd met on the Door Trail in the Badlands! Small world, hey?

There are two ways to get across Jenny Lake. You can hike two miles (each way), or you can buy a ticket for a boat ride.

We opted for the boat ride.

Why cross Jenny Lake?
Two reasons. First, the other side of the lake provides access to the very edge of the mountain range. Second, it brings you to the head of Cascade Canyon Trail.

There are many beautiful things to see on the Cascade Canyon Trail. It crudely follows the course of a swiftly flowing stream. At low elevation, the stream spills through several beautiful rapids. Alas, the trail makes for a pretty steep climb. So Ma hung back at one of the river crossings. I continued solo to Hidden Falls.

You hear the roar first. It gets louder as you draw nearer. The trail then wends its way into a deeply shadowed glen. The temperature drops dramatically. As you approach the split rail fence, the waterfall unfolds in front of you. So beautiful!

The trail continues up the mountain. There were several lookouts to Jenny Lake, like this one.

I paused to rest at the lookout, and this golden-mantled ground squirrel joined me.

The ultimate destination of the trail is called Inspiration Point. I hear it's the best lookout of Jenny Lake. But I'd had my fill, plus Ma was waiting below. So, I decided to head back.