Half Dome

On the fourth day, Polly decided to climb Half Dome. Not on the famous cable route up the back (it was closed for the season anyway), but in the air. Half Dome's north face rises almost straight up from the valley floor. It is 1,500 metres of smooth granite, polished by a glacier 15,000 years ago.

She started at first light. She flew from a pine grove near Mirror Lake and climbed slowly in spirals.

At three hundred metres up, she joined a flock of white-throated swifts. There were dozens of them. They were the fastest small bird Polly had ever flown with. They flashed and screamed past her. Polly was the slowest bird in the air. The swifts did not seem to mind.

The wind picked up at five hundred metres. The granite was already warm from the sun. Warm rock heats the air above it. Hot air rises. Rising air lifted Polly. She climbed in long arcs, letting the rock do the work.

Halfway up, she rested on a small ledge. From there she could see the cable route. The metal cables lay along the bare rock like a long thin spine. They were closed for spring. By July, hundreds of people a day would climb them.

At the top, the granite was flat. A hundred metres across, slightly tilted, with a few small piles of stones where humans had marked their summits.

She walked to the edge of the diving board, the famous overhanging slab, and looked down. The valley was a small ribbon below. El Capitan was so close she felt she could fly to it. The trees on the canyon floor looked like fuzz.

She stayed at the edge a long time. Then she pushed off the lip in a small calm dive and pulled up almost immediately to glide along the curve of the dome on the way down.