Occasional fires ravage parts of the park with the loss of thousands of acres of forest. Lightning is most often the cause, but man-made fires also take their toll. An out-of-control prescribed burn in August 2009 in the Big Meadow area near Foresta devastated nearly 8,000 acres. These unpredictable phenomena are reminders of Yosemite’s dynamic state.
How Half Dome Was Formed
Half Dome is estimated to be nearly 90 million years old. It is the signature landmark of Yosemite and is truly an American and a global icon. (It was the inspiration for the logo of the North Face company.) It is one of the planet’s most vertical walls, with the face rising 2,000 feet straight up. Its peak reaches an altitude of 8,842 feet. The distinctive face reflects Earth’s primordial power. Unlike most domes in the park, such as Liberty Cap, it is not a true spherical dome. When viewed from the west, it appears as a rounded table rather then the half-ball image it presents from other angles. It’s estimated that only 20% of the original dome is gone.
Only 20% “missing”
The exact method of Half Dome’s formation is not totally understood. When I moved to California, I was told straightaway that it was cut in half by glaciers. That explanation makes sense, and it certainly looks that way, but that is mostly wrong. It is true that Half Dome’s shape was influenced by glaciers; the northern and southern sides were affected about halfway up. Even John Muir believed it was glacial in origin. Yosemite likely has more granite domes than anywhere else on Earth, and most were indeed formed by glaciers. However, today’s geologists feel certain that Half Dome stood above the glaciers, as did many of the higher peaks in the park. No classic striations are on its surface or upper slopes. Another telltale sign is the erratic that rests at the Diving Board (western edge of the face) at 7,500 feet. An erratic is a large boulder that the glacier carries along and then gently puts down as it retreats. This boulder has the same material as the Cathedral Peak granite and is not the same as the Half Dome granodiorite that makes up the Diving Board. Clearly, this erratic was deposited by a glacier at that point.
When viewed from the air or from Washburn or Glacier points, Half Dome appears as part of a ridge along Tenaya Canyon. Scientists call this ridge a vertically oriented joint. The internal compression pressure in the rock causes it to develop joint plates that align themselves with the surface, regardless of the slope of the surface.
Glaciers did carve the lower ends of Half Dome, up to about 700 feet from the top, resulting in overhangs. These overhangs were released by the exfoliation action of the joints over time. So, it is safe to say that we don’t know definitively how Half Dome got its shape, but the face was probably caused by rockfalls and exfoliation along a prominent vertically oriented fracture on the famous north face, and glaciers probably did most of the sculpting of the smoother south face. Regardless, it is unique and beautiful.
Humans in Yosemite
Climb the mountains and get their good tidings. Nature’s peace will flow into you as sunshine flows into trees. The winds will blow their own freshness into you, and the storms their energy, while cares will drop off like autumn leaves.
—John Muir
Native Americans
The earliest Native Americans arrived in the area about 8,000 years ago. By the time of the European explorers, the Native American tribes in the greater California region included about 90 distinct entities. The Spanish were the dominant foreigners, and they focused their activities on religious conversion and raising cattle. The burgeoning Mexican territory meant they were spread thin in the west. The Native Americans living here were mostly agrarian and did not unify into a strong fighting machine, as did the Sioux, Cherokee, or Lakota of the plains. They did not rebel against the Spaniards. From 1769 to 1823, the Spaniards began a rigorous mission construction program, wherein each of 21 California missions was located about a day’s walk from the next. The missions ranged from Mission San Diego de Alcalá in the south to Mission San Francisco Solano, in Sonoma, to the north. The goal of converting the locals consumed much of the daily life for the Spaniards, and they did not venture deep into the Sierra but instead built settlements in the coastal and central valley areas. In the mid-1800s some of the tribes in the Sierra area were the Po-ho-nee-chees, Po-to-en’-cies, Wil-tuc-um’-nees, Noot’-choos, Chow-chil’-las, Ho-na’-ches, Me’-woos, Monos, and the Chook-chan’-ces. Today some of these names live on at Native American casinos in the area.
The tribe that called Yosemite Valley home was related to the Miwok and Mono Paiute. They called themselves Ahwahneechee, which is believed to mean “place of the gaping mouth.” (The entrance to the valley resembles such.)
Arrival of the Whites
By the early 1800s the American frontier of the time lay to the west of St. Joseph, Missouri. There were no towns or settlements to speak of farther west. The mountains of the High Sierra were unknown to the Anglos who were migrating westward. The exploratory journey of Meriwether Lewis and William Clark provided the first organized route to the new western continent. Surprisingly, it was the East Coast and European fashion industry that helped drive western exploration. Furs had become the wrap of choice for society women in Boston, Philadelphia, New York, and Paris. The high price that soft beaver pelts could bring trappers spurred on an industry to seek the mammals. Trails penetrating the Rocky Mountains began to appear, and thousands of beavers and other fur-bearing animals lured rugged trappers onto uncharted lands. The players in this cottage industry would meet annually to trade their bounty for cash with resellers. Yearly meetings (not unlike the buyer-seller conventions of today) were called rendezvous. Trappers, guides, suppliers, and ambitious men would recruit hunting parties to venture into the unknown. Skilled Native Americans were allowed to participate in a gesture of equality. In July 1833 the rendezvous was held on the banks of the Green River in Utah. It was here that a man named Captain Joseph Walker assembled a fur-hunting party. His goal was to find a direct westward route for trappers through the Central Sierra to the Pacific Coast. (The first westward expedition to California was accomplished by Jedediah Smith in 1826, but that route was via the easier southern Sierra and into San Diego.) Historical research into the journals of one member of the Walker party, Zenas Leonard, allows us to reconstruct the Walker route with some confidence. It appears the men traveled west to Salt Lake, and then followed the Humboldt River into western Nevada and on to Mono Lake before attempting to cross the High Sierra. The expedition then passed by the East Fork of the Walker River and by areas we know today as Glen Aulin and Tenaya Lake. Of interest here is the very high probability that they actually continued on and looked down into Yosemite Valley from a vantage at Yosemite Point. Their descriptions appear to accurately reflect this. The party did not descend into the valley but continued on their quest through Crane Flat, Merced Grove, and then along the lower Merced into San Francisco, Gilroy, and finally Monterey. Extensive research, including hiking these trails, by authors Grant Hiskes and John Hiskes (The Discovery of Yosemite 1833) helped confirm these facts.
Today the National Park Service takes care to get the involvement of many tribes when they conduct projects that impact the park. Specifically, the following are consulted: American Indian Council of Mariposa County, Bishop Paiute Tribal Office, North Fork Mono Rancheria, Bridgeport Paiute Indian Colony, Picayune Rancheria of Chukchansi Indians, Mono Lake Kutzadika’a Paiute Tribe, and the Tuolumne Band of Me-Wuk Indians.
A few others are thought to be the first to see Yosemite Valley. One could have been James Savage. He ran trading posts in the region, managed to marry five Native American women, and spoke their language. When both his Fresno River and South Fork trading posts were raided by Native Americans and some deaths resulted, it is highly probable that he pursued the renegades up the Merced River Valley and eventually