Yosemite

Bridalveil Creek is one of the handful of streams that feed water into the valley [src wikipedia:Yosemite Valley]. Here it arrives the way most of the valley’s water does — over the lip of the main canyon and straight down its wall. The reason is the shape of the place. The deep valley was cut lower and faster than the small side canyon behind the fall could keep pace with, so the creek now reaches the edge and simply drops, hundreds of feet, to the floor. The fall runs hardest in spring, when the snow on the high country above is melting fastest and the creek is full [src wikipedia:Yosemite Valley]. That is when it thunders and throws spray across the whole viewpoint. In a dry late summer the same fall thins to a pale ribbon, or breaks into a drift of mist that never quite reaches the ground. It is worth remembering that the cliff it pours over is granite — rock that formed deep underground and came up hard [src macrostrat:unit:3192002]. The water has been finding its way down anyway.

A single thin thread of water falls down the sheer wall near El Capitan. Ribbon Fall has no lake or large creek behind it — it is fed only by snowmelt and spring rain gathering on the rim above. That makes it a creature of the season. When the snow is melting it runs full and loud down bare rock in one long unbroken drop; once the melt runs out it falls quiet, and through high summer it often stops altogether. It follows the same rhythm as the valley’s other low-water falls, which draw from small drainages and are usually dry by midsummer [src wikipedia:Sentinel Fall]. This is the honest character of a granite country: the rock holds almost no water, so what falls as snow runs off fast and dramatically in spring and is gone by the dry months. The wall it pours over is the same hard granite that cooled deep underground long before any of this water existed [src macrostrat:unit:3192002]. The fall is young and seasonal; the cliff is old and patient.

This is the foot of the highest waterfall in North America [src wikipedia:Yosemite Valley]. From the trailhead a short, nearly flat walk brings you to the base of the lower fall, close enough to feel the cold air the falling water pushes ahead of it. The full trail to the top is a different matter — long and steeply switchbacked, climbing the entire height of the valley wall, work for a strong half-day or more. The fall is most prominent in spring, when the meltwater feeding it is at its peak [src wikipedia:Yosemite Valley]. That is when it fills the upper valley with sound and sends spray far out from the base. By late summer, with the snow gone from the high country, the same fall can slow to a thin trickle or stop entirely, leaving a dark streak on the cliff where the water usually runs. However you see it, the water is dropping the full depth the valley was cut — arriving from a creek on the plateau above that the deepening valley left stranded high on the wall.

A slender fall spills down the eastern flank of El Capitan, fed by snow and rain caught on the granite shoulders high above. Like the valley’s other thin falls, it runs only when there is water to feed it: lively in late winter and spring, dry through much of the rest of the year. What sets this spot apart is the backdrop. The fall drops in the open down a clean stretch of rock, with the vast pale face of El Capitan rising beside it — one of the high granite walls that stand over the valley [src wikipedia:Yosemite Valley]. The contrast is the lesson. It takes surprisingly little water to make a fall this tall; what matters is the height of the drop, and the height was made by ice and water working on the granite over a very long time [src macrostrat:unit:3192002]. Come when the snow is melting and there is a good chance the fall is running; come in the dry season and you may find only the stain where it was.

At the west end of the valley the Merced River runs wide and quiet, with El Capitan standing on one side and Bridalveil Fall coming down on the other [src wikipedia:Yosemite Valley]. This is the river that drains the entire valley [src wikipedia:Yosemite Valley]. Every creek and every fall in this note eventually gives its water to the Merced, and here, near the valley’s mouth, it gathers all of it and carries it out toward the lowlands. The character of the river has changed by the time it reaches this point. Up in its higher canyon it tumbles and cuts; here it is slow and level, spreading sand and gravel across the flat floor [src macrostrat:unit:2537610]. That is the gentlest stage of the same long work that carved the whole valley — the river no longer digging down but laying its load out smooth. It is an easy place to stand and take in both ends of the story at once: the tall cut walls above, and the level, river-built floor below.

Near the east end of the valley the Merced River comes down out of its steep upper canyon and slows abruptly onto the flat floor [src wikipedia:Yosemite Valley]. This is the hinge of the river’s story. Above here it is a tumbling, cold, loud mountain stream, still actively cutting into rock; below here it becomes the calm, wide water you see at the valley’s west end. From the trailhead a short walk reaches the riverside, and a strenuous trail climbs on beside the water toward the falls in the canyon upstream — a long, steep, rewarding half-day if you take it. But you do not have to climb to read the change. The place where fast water meets flat ground is right in front of you, and it marks the edge of the work the ice and river have already finished. Come in spring and the river here runs high and fierce with the melt; come later in the year and it drops and quiets, the same water doing the same job at a gentler pace.

A short walk up Tenaya Creek leads to a wide, still stretch of water that holds the cliffs above it in reflection [src wikipedia:Yosemite Valley]. It is less a true lake than a slow, shallow place in the creek, and it changes hard with the season. In spring it fills brim-full and glassy with meltwater; through summer it shrinks steadily; by autumn it can be a bend of sand and meadow with the creek reduced to a quiet channel. That seasonal disappearing act is itself the point. Everywhere else in the valley the water is falling or rushing; here it spreads out wide enough to slow almost to stillness, and stillness is what lets it work as a mirror. The creek is on its way to join the Merced on the valley floor, part of the same drainage that gathers at the west end [src wikipedia:Yosemite Valley]. Catch it early in the year and early in the day, before wind and heat have their say, and it is the calmest water in a valley otherwise defined by water in a hurry.

From this cliff-edge lookout the whole valley opens out below — the flat green floor, the Merced River threading through it, and Half Dome standing across the way [src wikipedia:Yosemite Valley]. It is the single best place to read the shape that water and ice have made. From the floor you cannot always see it, but from up here it is unmistakable: a broad, deep, flat-bottomed trench cut down into solid granite [src macrostrat:unit:3192002]. The walls fall away steeply; the floor lies level and green far below. You are standing roughly at the height the land once held all the way across, before the cutting began — everything below you has been removed, carried out grain by grain and boulder by boulder by the river and the ice. The high viewpoints like this one are reached only after the winter snow melts back from the road, so this is a warmer-season overlook. On a clear day, with the valley laid out beneath you, the argument between the rock and the water is not something you have to imagine — it is the view.

A little below Glacier Point, this lookout faces up the Merced’s canyon, toward the country where the river comes down through a run of steep drops before it reaches the valley floor [src wikipedia:Yosemite Valley]. Where Glacier Point shows you the finished valley, Washburn Point shows you the work still in progress. Here the river has not yet leveled its bed; it descends in steps over bare granite [src macrostrat:unit:3192002], each drop a place where the rock is harder or the cutting is younger. It is the same process that made the broad valley below, caught at an earlier stage. Half Dome and the high country stand above it all. Give the view a moment and the two lookouts read as one lesson in sequence: upstream, the river is still cutting a steep canyon; downstream, it has already opened a wide flat valley. The only difference between them is time, and the river has plenty of that.