Just How Big is Mt. Shasta in Northern California? Getting a sense of scale...

Mt. Shasta is a big mountain. It becomes visible from upwards of a hundred miles away. Topping out at 14,180 feet (4,322 m), it has the greatest volume of any Cascades stratovolcano at around a hundred cubic miles of lava flows and ash (the less visible shield volcanoes like Medicine Lake Highland are larger however). Driving north on Interstate 5, the mountain edifice takes on the very definition of "looming".

On our recent journey through the Pacific Northwest, Mt. Shasta was our first lecture stop. We drove up the flank of the mountain to an elevation of 7,000 feet or so at Bunny Flat, where we were stopped by snowdrifts...in late June. It's been a wet year!

It's hard to get a true sense of scale sometimes when observing really big mountains, but my camera has a pretty dandy zoom lens, so I had a bit of fun with it. In the picture above, note how the center of the picture is completely snowbound, except for three rocks near the top of the ice slope. I zeroed in on it.

In the photo above, we can see those three large rocks a bit more clearly. Keep in mind that we are already 7,000 feet up the mountain. There is more than a mile of mountain above us.

Zooming in once more, we can see that there is more than just three big rocks on the slope. It's hard to get a sense of how big they might be, except that at this scale we can see some more very small black dots scattered about the slope. What could they be?

At the highest zoom (60x), the small dots resolve into human beings. It was a hot day in the valley, so a lot of people were up on the slopes of Mt. Shasta keeping cool. And yes, Shasta is a very big mountain.

A Sight That Overwhelms: Dante's View and a Sense of Scale

It's one of the most astonishing viewpoints in all of North America. The Black Mountains form the eastern edge of Death Valley, and they are one of the most rugged mountain fronts in existence. In places the mountains are so steep that one cannot see the slopes at the base from the summit. Looking up from the lowest point in North America, Badwater, one can barely contemplate walking or driving to the summit across the barren cliffs.

And yet a road does just that. Taking advantage of the asymmetrical nature of the range, a paved road winds up the eastern flanks, and only the last few hundred yards of the drive are a vertiginous nightmare. And then there is a view like no other.

Death Valley is the largest national park in the lower forty-eight states, and Dante's View takes in much of the park, offering on clear days a view that extends across more than a hundred miles of desert ranges and salt flats. The view is so unlike any other place on the planet that George Lucas used it as setting for his alien planet in some movie about wars across the stars ("Mos Eisley spaceport. You will never find a more wretched hive of scum and villainy.").

Even though the summits reach nearly 6,000 feet above sea level, the slopes are barren and dry. The range lies in the rain shadow of the Sierra Nevada and two other high mountain ranges, including the Panamints that rise to 11,000 feet on the other side of Death Valley. In any other mountain range, 6,000 feet would support a thick forest. Here in the Black Mountains, only sage and seasonal wildflowers can grow.

The lack of vegetation is a boon to the geologist, of course. The exposures of bedrock are unparalleled, revealing a great deal about the geologic history of this part of the world. And it is a strange story. Much of the mountain range is composed of the Black Mountain Metamorphic Complex, a selection of gneiss and schist sequences that reveal evidence of a titanic series of plate collisions 1.7 billion years ago. At that time, North America was hit by a series of terranes, island systems maybe the size of New Zealand or California. The collisons produced a mountain range hundreds of miles long that would recall the coastal ranges of southern Alaska, minus the rainforests (terrestrial life didn't arise for at least another 1.2 billion years). These rocks are related to those found in the depths of the Grand Canyon and farther south in Arizona and New Mexico.

In the ensuing years, the vast range would be eroded to a nearly flat plain, and the surface would eventually subside below sea level. Tens of thousands of feet of Paleozoic sediments covered the rocks so they lay hidden deep in the continental crust. In the last few tens of millions of years, the regional crust was stretched and extended, and the overlying rocks slid away, causing the Black Mountains to "pop up" in the geologically short stretch of two or three million years. The exposure of the deep crust was accompanied by violent caldera eruptions, and parts of the mountain range are covered by colorful ash deposits (the rocks along Artists Drive Loop are particularly memorable).

Some places are so overwhelming that one can lose a sense of scale while staring into the abyss. Take a look at the picture below: we are looking at the vast salt pan of the Badwater Basin, the lowest place in North America at minus 282 feet. The salt flats cover 110 square miles. How big an area is this?

To find out, take a look at the thin channel of salt marked with the arrow in the picture above. We'll zoom in a bit, and find that we are looking at a spot next to the Badwater parking lot, which is just out of sight at the bottom of the picture. One can make out the Badwater Road on the left side of the photo. What are those dots on the salt channel? Let's zoom in a bit more (120x by now).

They're tourists! Badwater is a main destination for visitors to Death Valley. The stop lies 5,700 feet beneath Dante's View, and only two miles west. These mountains are about as steep as any can be.

The view from Dante's View on this afternoon in February was unique for me. Flash floods in October had destroyed some roads in the park, and I found it necessary to alter our usual itinerary. We usually see the viewpoint in the early morning. Until this day I had never seen the sun set over desert like this. It was an astounding sight. Even overwhelming...

Vernal Fall in Yosemite and a Sense of Scale (or, How to Feel Very Small)

It's a sense of scale that helps us keep perspective. I was at Washburn Point in Yosemite National Park today, and I took a few shots with the zoom of the same spot across the way.

We have a bunch of people apparently enjoying themselves on a flat slab of rock next to a fair sized river. But why the fence? Why aren't they letting people cool their feet in the river on this reasonably warm day?

Maybe it is the fact that they are standing at the top of a 318 foot (97 meter) waterfall. And a hell of a dangerous one. It is far too easy to miscalculate just how powerful a flowing river can be. Water only a foot deep can easily knock you off your feet, and the rock can be exceedingly smooth from glacial erosion and slick with algae. Too many people on the wrong side of the fence have lost their lives.

As we pull back even more, we can see the full extent of the waterfall, and the insignificance of the people gathered around the brink. They are now barely visible. This is Vernal Fall on the Merced River just upstream of Yosemite Valley. It formed because the glaciers that once flowed through the valley plucked away at highly jointed rocks forming what is called a glacial stairstep. It is just one of many spectacular waterfalls in Yosemite that leave one feeling awestruck.

And yet, Yosemite is such an incredible landscape of gigantic granite domes and deep glacially carved gorges that even a 318 foot waterfall can almost be lost in the richness of scenery. As I noted before, I was on Washburn Point, about two miles away as the crow flies (or more probably the raven, given their abundance here) from Vernal Fall. In the picture below, Vernal is the smaller of the two gigantic waterfalls. The upper one is Nevada Falls, which drops 594 feet (181 meters). 

To the left of Nevada Falls is Liberty Cap, a glacially smoothed granitic dome. To the left of Liberty, the dark rounded form of Half Dome is seen from an unfamiliar angle. From this angle it is clear that if anything, it should be called Three-Quarters Dome, or even Four-Fifths Dome. 

Half Dome was never covered by glacial ice, and was formed instead by exfoliation, the tendency of rocky monoliths to break off slabs of rock as the pressure is released as the rock is exposed at the surface. The slabs mostly remove corners and edges, giving the rock a rounded profile. The steep face of Half Dome was a prominent joint, a vertical crack that also forms from pressure release. The "missing" half was undercut by the glacier below in Tenaya Canyon and quarried away down the valley.

Feeling small yet?