The Smell of Rain

Walking toward the Columbia River early this morning, the old dirt road we traveled was dry and I could still see my own footprints from yesterday. The sky was partly sunny and with the temperature hovering in the mid-fifties, I had elected to leave my jacket in the car.

Nicholai, Izzy, and I enjoyed a pleasant trip along the trail and beach, while in the distance gray clouds gathered. As we made our way up a sandy trail, a sudden pattering on the leaves of branches overhead alerted me the clouds had moved our way, and in just a moment we were pelted with warm spring rain.

Immediately, I was immersed in a smell at once familiar and yet not understood – the smell of rain. Sweet and earthy, slightly musky, my nostrils delighted in the piquant scent. As the raindrops pounded our heads, I began to trot along at an easy run, but it was hopeless – we were going to get drenched.

As we all jogged along the trail, Izzy out front heading for the cover of the car and Nicholai loping at my side, I sucked in more of that sweet fresh-rain aroma, and for the first time, I wondered why it smelled that way.

It turns out there's a bacteria in the soil – actinomycetes – common all over the world. Actinomycetes produce spores when the soil is dry. The wetness and force of falling rain kick the tiny spores into the air where the moisture acts as an aerosol – just like an aerosol room freshener. We breathe the spores carried in the moist air and – voila – the fresh smell of rain that is universally experienced all around the world.

Our jog toward the car took us past a huge deposit of river rock where a second welcome scent accosted my nostrils – the smell of rain-washed rocks. The river delta area is dense with plants –towering cottonwood trees, wild roses, red-osier dogwood, ferns, and grasses taller than I am. All of these plants manufacture volatile oils in their leaves and flowers which are released and collect on rocks. Rain washes the rocks, mixing with the plant oils, and alchemizing them to the gaseous perfume which wafted to my nose.

By the time we reached the car, my hair was plastered to my head, Nicholai's thick fur was dripping and Isabella was more than ready to jump into the sanctuary of the vehicle. The soaking didn't matter to me; I was high on spring rain scents.