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Yosemite Valley is located on the western slopes of the Sierra Nevada mountains of California. It is a tight walled, U-shaped space that contains some of the most impressive alpine scenery in the world. Most tourists enter Yosemite Valley after a long drive on roads that hug steep hillsides (with very few guard rails!). Last summer’s massive wildfires have blackened many of these down-slope and up-slope vistas (photo below). Then the road goes through a tunnel that is cut through the granite of one of the western-edging mountains, and then, suddenly, you are in the valley. The tunnel is quite beautiful in itself! Its granite walls and ceiling have been left exposed and their reflective, heterogeneous mineral crystals glitter in the headlights of the passing cars.
Outside the tunnel is a small parking area logically named “Tunnel View” from which most of the landmarks and the sights of the valley can be seen. Even on the days with very light traffic (which are few and far between in this extremely popular destination) the small parking area is usually full requiring a drive further down the road to find a roadside parking spot often several hundred yards away.
Our choice in coming to Yosemite in the third week of May was guided by several considerations: 1. We hoped that there would be fewer other tourists here in the week before Memorial Day, 2. The weather should be dry and relatively warm so that we would be able to hike (historical weather data culled from the records at The Weather Underground predicted low 70’s F for highs and low 40’s F for lows with “0”inches of expected rain), 3. The melt of the winter’s snow from the high, surrounding mountains, should fill Yosemite’s famous waterfalls to their maximum, and 4. The early wildflowers should be riotously abundant in the high meadows!
The actual weather for our days in Yosemite, though, was a little bit different than we expected. The temperatures were only slightly cooler, but each day had a 40% chance of rain! An “unusual” weather front had come into the mountains from the Pacific Ocean (it is hard, though, to call any weather pattern in these days of climate change “unusual!”) and dumped several inches of cold rain on us during our Yosemite stay. The rain clouds, at times, enshrouded the great, granite domes of the park making very dramatic impressions and photographs, but they also made the rocky trails quite slippery. These clouds and showers, though, kept the crowds away (or confined them to the tourist centers and coffee shops!) and gave us a much more individual Yosemite experience than we would have thought possible even in this week before the start of summer season.
So cloaked in ponchos and rain jackets with warm layers underneath, we struck off into the park! The waterfalls, by the way, were spectacular!! Our first short walk was out to Bridal Veil Falls just down the road from Tunnel View. The water flow was so massive there that a “soak zone” extended out more than 50 meters from the actual falls. Everyone who tried to walk out to see the falls got drenched!
Later that day we walked to the Lower Yosemite Falls. It is a much larger, but much more “civilized” waterfall! We could stand near the lower cascade and be surrounded by its incredible roar but not be pummeled by sheets of icy water! The drop of the three segments of Yosemite Falls covers just over 2400 feet making it the highest waterfall in North America. It was hypnotically impressive and was also an easily seen landmark and reference point from many places in the park.
The Sierra Nevada are very young mountains. They are made up primarily of a mass of granite that formed deep in the Earth some 100 million years ago. This granitic mass began to rise and tilt about 10 million years ago forming the mountain range. The uneven tilt of this rock generated sheer cliffs and high rock faces to the east and the relatively gradual set of rising elevations to the west.
The rising granite pushed up through the overlying, sedimentary rock. This rock overburden, unlike the granite, was quite erodible and through action of wind, water, ice and snow, was steadily ground away to reveal the surface of tough granite. Great cracks (called “joints”) formed in the rising granite. Some of these joints were vertically oriented and some were horizontal, but others were arching and rounded. These rounded cracks formed the curving surfaces of the granite domes that dominate the Yosemite landscape. These domes are only very slowly eroding, and, because of their surface geometries and the impacts of rain, ice and snow, they are constantly scoured of accumulating mineral debris. Soils do readily form on these granite domes and they stand, predominately uncloaked by vegetation!
Yosemite Valley was repeatedly carved by glaciers during the Ice Ages of the Pleistocene. The U-shape of the valley is distinctively a product of glacial sculpting. John Muir first proposed the glacier theory for the valley’s origin and used the still forming glacier valleys in Alaska as models to support his theories. Muir extensively described and studied the glaciers of Yosemite and, eventually, after a long acrimonious debate with formally trained geologists, his theories prevailed. There are still some glaciers in Yosemite lurking in the shady, north facing slopes of the mountains, but 75% of the glaciers that John Muir studied are gone due to the ongoing warming trends of Climate Change.
In our days at Yosemite we hiked around the western loop of valley floor and walked right up to the base of El Capitan. Two climbers were working their way up the sheer face of the mountain the morning we were there. We watched them with a mixture of envy and dread. A group of us also climbed the long, steep, rocky steps up to Vernal Falls in a light, steady rain, while others explored the Merced River and the trail to Mirror Lake. We also walked around the giant sequoia grove at Mariposa and the wet meadow of Wawona and were finally able to drive up Glacier Point Road (after the newly fallen snow had melted sufficiently) to go to Glacier Point (the site of the famous photo of Theodore Roosevelt and John Muir) and take in the dizzying overview of the entire valley. Snow still blocked many areas of the park, but everything we saw was incredible!
And, finally, I want to talk about an aspect of Yosemite that is much less visible to most visitors than the great rock masses or waterfalls. Yosemite National Park (which contains Yosemite Valley) is a protected refuge for an amazing number of plants and also a good number of animals. California has the greatest biodiversity among the 50 states. It has 7000 plant species and 20% of these are found within the boundaries of the Sierra Nevada and Yosemite. Two hundred of these plant species are, in fact, found nowhere else in the world! We were a bit early for the blooming of many of the Yosemite species, but we did see a rich array of beautiful plants (Deborah identified 30 of them!) including snow plant (pictured above), Indian paintbrush, Brewer’s lupine, California poppy and smoothstem blazing star.
We also saw some common animals and tried to find a few uncommon ones. Mule deer, chipmunks and ground squirrels made up most of our mammal sightings (although we did see one coyote). We didn’t see any black bears or big horned sheep. We saw no snakes but did encounter a fence lizard up on the rocks of Glacier Point (picture to the left)! Of the 150 species of birds that have been reported from the park, we only saw eleven. The most abundant were ravens and robins but the western tanager, spotted towhee and acorn woodpecker were wonderful, although, fleeting sights!
The animal I really wanted to see, though was the endangered, Yosemite toad (Amaxyrus canorus (formerly Bufo canorus)). At times we were up in the right altitude zone for these toads (6389 to 11,302 feet) but the snows had not sufficiently melted to shake the toads from their winter hibernation or generate their breeding pools. Maybe another week or two, and they would have been active. The unusual color dimorphism of the male and female Yosemite toads (males are a uniform yellow-green to greenish-brown while females are dorsally black and covered with distinctive copper-colored blotches that have white-cream borders) reflect two remarkable gender-specific, natural selection matrices for these extremely high altitude dwelling amphibians. Also the common name for this species (the “tip-toe toad”) describes a particular evolutionary derived mode of locomotion that allows them to walk across snow fields without dragging their bodies on the cold snow surface! They would have been a wonderful creature to see!
Yosemite was an incredible place to visit. I can’t believe that it has taken me so many decades to finally get out there, but it was worth the wait! I am glad that we went when the weather was not ideal, too. It gave us the opportunity to see the park with just the right number of fellow human beings.