This past fall, I took my first trip to Yosemite National Park. I went for a weekend with a good friend, Jo, who I met while traveling through South America. We had made plans to explore Yosemite together when saying goodbyes in Bolivia and we were incredibly excited to journey such a renowned reserve of nature.
After a long drive from Stanford, we found ourselves in the park and in the midst of the first rainfall in months. California, suffering the crippling effects of the worst drought in over a thousand years, gratefully welcomed the active gray clouds. I, on the other hand, worried that the rain might spoil our adventures for the weekend.
I was wrong. The rain was a blessing, offering a heightened experience of both sight and smell.
One of my favorite words is petrichor. It’s a wonderfully specific word meaning “a pleasant smell that frequently accompanies the first rain after a long period of warm, dry weather.” The word comes from Greek, a combination of petros (“stones”) and ichor, the fluid that flows like blood in the veins of the gods.“
The word first appeared in a Nature journal article from 1964 with an enticing title: Nature of Argillaceous Odor. Two researchers, Bear and Thomas, posited in the original article and a follow-up a year later that the unique smell was a result of an oil released by plants during times of duress causing a retardation of seed germination. In simpler terms, the oil is a way to prevent plants from trying to grow in a resource challenged setting, a stop sign for nature. As the oil is released, it, seeps into clay-based soils and rocks. During a rainfall, the water disperses the oil molecules into the air, producing the unique smell, one borne of a meeting between a survival mechanism and a quintessential component of our cycle of life, rain. (For a more visual explanation, see the It’s Okay To Be Smart Video, "Where Does the Smell of Rain Come From?”)
As Jo and I hiked the tough Upper Yosemite Falls trail the first day, petrichor greeted our nostrils. If there was a time to encounter petrichor, it was during a rainfall in the midst of a severe drought. The smell opened my awareness to the other senses and I began to notice something spectacular: the effect of the rain on my visual field. The greens felt brighter and the browns richer, as if the rain had unlocked a deeper layer of color. The rain had stripped the thin veneer of reality. Looking at the trail, the trees, and the sky, I felt like time was suspended.
Surely, this perceptual boost is an explainable one. It likely something to do with the reflection and refraction of light, that, when combined with dispersion, give us the phenomena of rainbows. Still, it’s tough to grapple with the experience with only the abstractions of science. Instead, maybe one of Jo’s great photographs can illustrate (for more great shots, check out his site):
Petrichor is a stop sign of nature, a defense mechanism. I think that petrichor and rain are also stop signs for us. Pause, petrichor says, witness the smell. Wait, rain beckons, take in the vivid colors. I wrote previously about the meditative life; perhaps petrichor and rain are meditative nature. Maybe they are gentle offerings of altered sensation. They are explainable and fascinating – the products of evolution and the properties of light and water – but they are best when they are experienced, not understood.
Today, take whatever gentle offering comes your way.