Yosemite

This roadside pullout looks straight up the length of the valley, and it is the clearest place to read the whole shape at once. The Merced River slides past in the foreground; beyond it the granite walls rise on both sides and the floor runs flat between them. That flat floor and those sheer walls are the reason this is called a glacial valley — a river working alone would have left a narrow V, tapering to the stream at its bottom, but ice left a broad, flat-bottomed trough. The river you see now is the modest stream that remains where a glacier once filled the entire opening. It is the first full view many people get of the valley, and the easiest to understand: everything else in this note is a detail of the shape you are looking at here. Late in the day the light comes down the valley toward you and the walls glow.

An interpretive board stands here at the western gates of the valley, where the walls pinch close and the Merced River leaves the flat floor. The spot is well chosen. This narrowing is where the ice spilled out of the valley it had been carving, and from here you can look back east into the broad trough it left behind. Read the board, then look up. The two great masses framing the gate — El Capitan on the left, the Cathedral Rocks on the right — are granite the ice ground past on its way out of the valley. It is a good place to hold two ideas together: the tight notch you stand in, and the wide basin behind you that the same ice hollowed out. The board itself names glaciers as the shaping force, which is exactly the story the ground here tells.

A nearly level path leads from here toward Mirror Lake, at the foot of the cliffs where Tenaya Creek enters the valley. The lake is the last open water of a much larger one. When the ice withdrew, a lake filled the valley floor; over time, sand and gravel filled it in until only this small pool remained. It is still filling. In the spring meltwater it spreads wide and, on a still morning, throws the cliff above back at you as a reflection; by late summer it often shrinks to a gravel flat and meadow. Either way, you are looking at the valley’s own future — the slow conversion of standing water into level ground, caught partway through. The flat floor you walked in on was once a lake exactly like this one.

El Capitan rises from the valley floor in one clean sweep of granite, a wall so sheer and so smooth it looks cut. Much of that is the rock itself: this granite cooled deep underground with few natural cracks, so it stands in great unbroken faces rather than crumbling into slopes. The ice did the rest, grinding along the base of the wall and steepening it as it passed. Stand in the meadow beneath it and the scale is hard to hold in the eye — the face keeps going up long after you expect it to stop. On a clear day you may pick out climbers as slow, bright specks partway up the stone, which is the only reliable way to feel how large it truly is. This is the plainest single lesson in why the valley walls stand the way they do.

Sentinel Rock stands on the south wall of the valley as a tall, tapering blade of granite — a watchtower shape that gives it its name. It is the same deep-cooled granite as the rest of the valley walls, worked into this steep pinnacle where the ice and the weather cut along its seams. Beside it in spring, a long thread of water comes down the cliff: Sentinel Fall, a tiered cascade fed by snowmelt that is usually dry by midsummer. Together the rock and the fall make a plain seasonal clock — the blade of stone is there all year, the ribbon of water only while the high country is still shedding its winter. It is one of the more distinctive silhouettes on the valley’s south side, and easy to find from the floor.

A short paved path leads to the foot of Bridalveil Fall, where a side stream leaps off the cliff and falls free to the valley floor. The waterfall exists because of how the ice worked. The main glacier cut the valley deep, but the smaller stream in its side canyon could not keep pace, so its floor was left hanging high on the wall when the ice withdrew. Now the stream simply runs off the edge and drops. In a breeze the fall drifts sideways and breaks into mist, which is where its name comes from. It runs strongest in spring, when the high snow is melting, and thins through the summer. Of all the valley’s waterfalls, this is the easiest one to walk to and the clearest illustration of a stream left stranded above the valley the ice deepened beneath it.

This trailhead sits below Yosemite Falls, where a creek comes off the north rim in a long series of drops — the highest waterfall on the continent. A short, mostly level path from here reaches the base of the lower fall; a much steeper trail climbs the wall beside it for anyone who wants the top, a strenuous half-day of switchbacks. Like Bridalveil, this is a side stream that was left hanging high when the ice deepened the main valley, and it now runs off the rim to make the descent in stages. It is loudest and fullest in the spring meltwater and quiets through the dry months, until in late summer it can dwindle to a faint streak. The sound of it carries a long way down the valley when the water is high.

Glacier Point stands on the valley’s south rim and looks down into the whole trough from above — the flat floor, the winding river, the domes on the far side, and the high country beyond, where the ice came from. From up here the U-shape reads at a single glance in a way it never can from the floor, where the walls crowd too close to see whole. The overlook is reached by a long road that climbs to the rim, open only after the snow clears the high country, generally from late spring into fall. The granite underfoot is the same rock that walls the valley far below — you are simply standing on the top edge of it now, looking down the cut. It is the one stop where the shape of the whole valley resolves into a single form.

A walk from the high road reaches the bare granite crown of Sentinel Dome, a rounded summit standing above the valley rim. Its smooth curve is granite shedding itself in layers: the rock peels away in great curved shells, like the skins of an onion, rounding every edge over time. That is a different shape from the sheared walls of the valley below, made by a different process — the walls were cut steep and fast, while a dome rounds itself slowly from the outside in. The two shapes sit within sight of each other, the rounded crown and the squared trough, both worked from the same granite. Reaching the top means a climb from the high road, open only once the snow has left, generally from late spring into fall. From the summit the high country runs out in every direction.